Code:
Use the following snippet to Shell the date/time dialog.
Substitute the codes below for other Control Panel dialogs. 
  
 
Call Shell("rundll32.exe shell32.dll,Control_RunDLL _ timedate.cpl")

 
Control Panel (CONTROL.EXE)
 
Control Panel:  
    rundll32.exe shell32.dll,Control_RunDLL
 
 
Accessability Settings (ACCESS.CPL) 
 
Accessability Properties (Keyboard):  
    rundll32.exe shell32.dll,Control_RunDLL access.cpl,,1
 
Accessability Properties (Sound):  
    rundll32.exe shell32.dll,Control_RunDLL access.cpl,,2
 
Accessability Properties (Display):  
    rundll32.exe shell32.dll,Control_RunDLL access.cpl,,3
 
Accessability Properties (Mouse):  
    rundll32.exe shell32.dll,Control_RunDLL access.cpl,,4
 
Accessability Properties (General):  
    rundll32.exe shell32.dll,Control_RunDLL access.cpl,,5
 
 
Add/Remove Programs (APPWIZ.CPL)
 
Add/Remove Programs Properties (Install/Uninstall):  
    rundll32.exe shell32.dll,Control_RunDLL appwiz.cpl,,1
 
Add/Remove Programs Properties (Windows Setup):  
    rundll32.exe shell32.dll,Control_RunDLL appwiz.cpl,,2
 
Add/Remove Programs Properties (Startup Disk):  
    rundll32.exe shell32.dll,Control_RunDLL appwiz.cpl,,3
 
 
Display Settings (DESK.CPL)
 
Display Properties (Background):  
    rundll32.exe shell32.dll,Control_RunDLL desk.cpl,,0
 
Display Properties (Screen Saver):  
    rundll32.exe shell32.dll,Control_RunDLL desk.cpl,,1
 
Display Properties (Appearance):  
    rundll32.exe shell32.dll,Control_RunDLL desk.cpl,,2
 
Display Properties (Settings):  
    rundll32.exe shell32.dll,Control_RunDLL desk.cpl,,3
 

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Display Properties (Install Screen Saver):  
    rundll32.exe desk.cpl,InstallScreenSaver %1
    (opens .scr at location specified by %1 in preview window)
 
 
FindFast Settings (FINDFAST.CPL) 
 
Find Fast Properties (General):  
    rundll32.exe shell32.dll,Control_RunDLL findfast.cpl
 
 
Internet Settings (INETCPL.CPL)
 
Internet Properties (General):  
    rundll32.exe shell32.dll,Control_RunDLL inetcpl.cpl,,0
 
Internet Properties (Security):  
    rundll32.exe shell32.dll,Control_RunDLL inetcpl.cpl,,1
 
Internet Properties (Content):  
    rundll32.exe shell32.dll,Control_RunDLL inetcpl.cpl,,2
 
Internet Properties (Connection):  
    rundll32.exe shell32.dll,Control_RunDLL inetcpl.cpl,,3
 
Internet Properties (Programs):  
    rundll32.exe shell32.dll,Control_RunDLL inetcpl.cpl,,4
 
Internet Properties (Advanced):  
    rundll32.exe shell32.dll,Control_RunDLL inetcpl.cpl,,5
 
 
Regional Settings (INTL.CPL)
 
Regional Settings Properties (Regional Settings):  
    rundll32.exe shell32.dll,Control_RunDLL intl.cpl,,0
 
Regional Settings Properties (Number):  
    rundll32.exe shell32.dll,Control_RunDLL intl.cpl,,1
 
Regional Settings Properties (Currency):  
    rundll32.exe shell32.dll,Control_RunDLL intl.cpl,,2
 
Regional Settings Properties (Time):  
    rundll32.exe shell32.dll,Control_RunDLL intl.cpl,,3
 
Regional Settings Properties (Date):  
    rundll32.exe shell32.dll,Control_RunDLL intl.cpl,,4
 
Regional Settings Properties (Input Locales):  
    rundll32.exe shell32.dll,Control_RunDLL intl.cpl,,5
 
 
Joystick Settings (JOY.CPL)
 
Joystick Properties (Joystick):  
    rundll32.exe shell32.dll,Control_RunDLL joy.cpl
 
 
Mouse/Keyboard/Printers/Fonts Settings (MAIN.CPL)
 
Mouse Properties:  
    rundll32.exe shell32.dll,Control_RunDLL main.cpl @0
 
Keyboard Properties:  
    rundll32.exe shell32.dll,Control_RunDLL main.cpl @1
 
Printers:  
    rundll32.exe shell32.dll,Control_RunDLL main.cpl @2
 
Fonts:  
    rundll32.exe shell32.dll,Control_RunDLL main.cpl @3
 
 
Mail and Fax Settings (MLCFG32.CPL)
 
Microsoft Exchange/Outlook Properties (General):  
    rundll32.exe shell32.dll,Control_RunDLL mlcfg32.cpl
 
 
Multimedia/Sounds Settings (MMSYS.CPL)
 
Multimedia Properties (Audio):  
    rundll32.exe shell32.dll,Control_RunDLL mmsys.cpl,,0
 
Multimedia Properties (Video):  
    rundll32.exe shell32.dll,Control_RunDLL mmsys.cpl,,1
 
Multimedia Properties (MIDI):  
    rundll32.exe shell32.dll,Control_RunDLL mmsys.cpl,,2
 
Multimedia Properties (CD Music):  
    rundll32.exe shell32.dll,Control_RunDLL mmsys.cpl,,3
 
Multimedia Properties (Advanced/Devices):  
    rundll32.exe shell32.dll,Control_RunDLL mmsys.cpl,,4
 

--------------------------------------------------------------------------------
 
Sounds Properties:  
    rundll32.exe shell32.dll,Control_RunDLL mmsys.cpl @1
 
 
Modem Settings (MODEM.CPL)
 
Modem Properties (General):  
    rundll32.exe shell32.dll,Control_RunDLL modem.cpl
 
 
Network Settings (NETCPL.CPL / NCPA.DLL)
 
Network (Configuration):  
    Win9x: rundll32.exe shell32.dll,Control_RunDLL netcpl.cpl
    WinNT: rundll32.exe shell32.dll,Control_RunDLL ncpa.cpl
 

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Dial-up Networking Wizard 
    Win9x: rundll32.exe rnaui.dll,RnaWizard
 

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Create Share Dialog 
    WinNT: rundll32.exe ntlanui.dll,ShareCreate
 
Manage Shares Dialog 
    WinNT: rundll32.exe ntlanui.dll,ShareManage
 
 
ODBC Settings (ODBCCP32.CPL)
 
ODBC Data Source Administrator (General):  
    rundll32.exe shell32.dll,Control_RunDLL odbccp32.cpl
 
 
Password Settings (PASSWORD.CPL)
 
Password Properties (Change Passwords):  
    Win9x: rundll32.exe shell32.dll,Control_RunDLL password.cpl
 
 
COM Ports Settings (PORTS.CPL)
 
COM Ports Properties (General):  
    WinNT: rundll32.exe shell32.dll,Control_RunDLL ports.cpl
 
 
Server Properties (SRVMGR.CPL)
 
Server Properties (General):  
    WinNT: rundll32.exe shell32.dll,Control_RunDLL srvmgr.cpl
 
 
System Settings (SYSDM.CPL)
 
System Properties (General):  
    rundll32.exe shell32.dll,Control_RunDLL sysdm.cpl,,0
 
System Properties (Device Manager):  
    Win9x: rundll32.exe shell32.dll,Control_RunDLL sysdm.cpl,,1
 
System Properties (Performance):  
    Win9x: rundll32.exe shell32.dll,Control_RunDLL sysdm.cpl,,3
    WinNT: rundll32.exe shell32.dll,Control_RunDLL sysdm.cpl,,1
 
System Properties (Environment):  
    WinNT: rundll32.exe shell32.dll,Control_RunDLL sysdm.cpl,,2
 
System Properties (Startup/Shutdown):  
    WinNT: rundll32.exe shell32.dll,Control_RunDLL sysdm.cpl,,3
 
System Properties (Hardware Profiles):  
    Win95: rundll32.exe shell32.dll,Control_RunDLL sysdm.cpl,,2
    WinNT: rundll32.exe shell32.dll,Control_RunDLL sysdm.cpl,,4
 
System Properties (User Profiles):  
    WinNT: rundll32.exe shell32.dll,Control_RunDLL sysdm.cpl,,5
 

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Add New Hardware Wizard:  
    Win9x: rundll32.exe shell32.dll,Control_RunDLL sysdm.cpl @1
 
Add New Printer Wizard:  
    Win9x: rundll32.exe shell32.dll,SHHelpShortcuts_RunDLL AddPrinter
 
 
Telephony Settings (TELEPHON.CPL)
 
Dialing Properties (My Location / Drivers):  
    WinNT: rundll32.exe shell32.dll,Control_RunDLL telephon.cpl
 
 
Themes Settings (THEMES.CPL)
 
Themes Properties (General):  
    rundll32.exe shell32.dll,Control_RunDLL themes.cpl
 
 
Time and Date Settings (TIMEDATE.CPL)
 
Date/Time Properties:  
    rundll32.exe shell32.dll,Control_RunDLL timedate.cpl
 
Choose Time Zone:  
    rundll32.exe shell32.dll,Control_RunDLL timedate.cpl,,/f
 
 
TweakUI Settings (TWEAKUI.CPL)
 
TweakUI Dialog (General):  
    rundll32.exe shell32.dll,Control_RunDLL tweakui.cpl
 
 
UPS Settings (UPS.CPL)
 
Uninteruptable Power Supply Properties (General):  
    WinNT: rundll32.exe shell32.dll,Control_RunDLL ups.cpl
 
 
Microsoft Mail Postoffice Settings (WGPOCPL.CPL)
 
Microsoft Workgroup Postoffice Admin:  
    rundll32.exe shell32.dll,Control_RunDLL wgpocpl.cpl
 
 
Miscellaneous File System Dialogs and Wizards
 
Open With (File Associations):  
    rundll32.exe shell32.dll,OpenAs_RunDLL d:\path\filename.ext
 
Run Diskcopy Dialog: 
    rundll32 diskcopy.dll,DiskCopyRunDll
 
Create New Shortcut Wizard: 
    rundll32.exe AppWiz.Cpl,NewLinkHere %1
    (creates shortcut at location specified by %1)
 
Create a Briefcase: 
    rundll32.exe syncui.dll,Briefcase_Create
 
View Fonts: 
    rundll32.exe shell32.dll,SHHelpShortcuts_RunDLL FontsFolder
 
View Printers: 
    rundll32.exe shell32.dll,SHHelpShortcuts_RunDLL PrintersFolder