Ok..... I've decided to make an WinAmp Plugin with C#. But I need some help!
I need to get in "touch" with the WinAmp window.
For VB this is:

Public Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Dim hwndWinamp as long
hwndWinamp = FindWindow("Winamp v1.x",vbNullString)

For C/C++:

HWND hwndWinamp = FindWindow("Winamp v1.x",NULL);

Delphi Pascal:

var hwndWinamp : THandle;
hwndWinamp := FindWindow('Winamp v1.x', nil);

But what is it for C#?

And... How can I use WM commands?