To write the DLL? When you start VB, select ActiveX DLL. If you want to make a simple DLL, I can give an example.

In the Class Module, put the following code.

Code:
Public Sub SayHello()

   ' Display a message box
   MsgBox("Hello World")

End Sub
Now, create the DLL, start a new Standard EXE and add Refrence to it. to add refrence, Select Refrences from the Project Menu.

Now, add a CommandButton with the following code.

Code:
Private Sub Command1_Click()

   Dim MyVar As Class1
   Set MyVar = New Class1
   MyVar.SayHello
   Set MyVar = Nothing

End Sub
This should pop up a message saying "Hello World!"