Hi this is the API that Changes the Form to Any Desired Shape. These Functions I used from other Guys, Program. If you need a Detail Description and usage, goto
http://www.planet-source-code.com, select source as vb from the right hand side link and from there you can see a project named skindemo. Get into it and download the code. It's really a good stuff...

But One Drawback is that, I can't Understand what the Code does....?

'Main Function to Change the Mask of a Basic Form...

Private Declare Function CombineRgn Lib "gdi32" (ByVal hDestRgn As Long, ByVal hSrcRgn1 As Long, ByVal hSrcRgn2 As Long, ByVal nCombineMode As Long) As Long
Private Declare Function CreateRectRgn Lib "gdi32" (ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) As Long
Private Declare Function DeleteObject Lib "gdi32" (ByVal hObject As Long) As Long
Private Declare Function GetPixel Lib "gdi32" (ByVal hDC As Long, ByVal X As Long, ByVal Y As Long) As Long
Private Declare Function ReleaseCapture Lib "user32" () As Long
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Declare Function SetWindowRgn Lib "user32" (ByVal hWnd As Long, ByVal hRgn As Long, ByVal bRedraw As Boolean) As Long

Private Const RGN_OR = 2
Private lngRegion As Long
Public Prg As String, Sect As String ' for savesettings
Public skindir As String


Function RegionFromBitmap(picSource As PictureBox, Optional lngTransColor As Long) As Long

'it lets your form me any shape. *

Dim lngRetr As Long, lngHeight As Long, lngWidth As Long
Dim lngRgnFinal As Long, lngRgnTmp As Long
Dim lngStart As Long, lngRow As Long
Dim lngCol As Long
If lngTransColor& < 1 Then
lngTransColor& = GetPixel(picSource.hDC, 0, 0)
End If
lngHeight& = picSource.Height / Screen.TwipsPerPixelY
lngWidth& = picSource.Width / Screen.TwipsPerPixelX
lngRgnFinal& = CreateRectRgn(0, 0, 0, 0)
For lngRow& = 0 To lngHeight& - 1
lngCol& = 0
Do While lngCol& < lngWidth&
Do While lngCol& < lngWidth& And GetPixel(picSource.hDC, lngCol&, lngRow&) = lngTransColor&
lngCol& = lngCol& + 1
Loop
If lngCol& < lngWidth& Then
lngStart& = lngCol&
Do While lngCol& < lngWidth& And GetPixel(picSource.hDC, lngCol&, lngRow&) <> lngTransColor&
lngCol& = lngCol& + 1
Loop
If lngCol& > lngWidth& Then lngCol& = lngWidth&
lngRgnTmp& = CreateRectRgn(lngStart&, lngRow&, lngCol&, lngRow& + 1)
lngRetr& = CombineRgn(lngRgnFinal&, lngRgnFinal&, lngRgnTmp&, RGN_OR)
DeleteObject (lngRgnTmp&)
End If
Loop
Next
RegionFromBitmap& = lngRgnFinal&
End Function

Sub ChangeMask()
On Error Resume Next ' In case of error

Dim lngRetr As Long
lngRegion& = RegionFromBitmap(Mask)
lngRetr& = SetWindowRgn(Me.hWnd, lngRegion&, True)
End Sub