Ya conseguí hacer lo que quería pero ahora no se como puedo hacer para saber si existe una cámara instalada y utilizable ¿?.
Gracias a todos.

Esta sección te permite ver todos los mensajes escritos por este usuario. Ten en cuenta que sólo puedes ver los mensajes escritos en zonas a las que tienes acceso en este momento.
Mostrar Mensajes MenúPublic Declare Function SendMessage Lib "USER32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Public Declare Function capCreateCaptureWindow Lib "avicap32.dll" Alias "capCreateCaptureWindowA" (ByVal lpszWindowName As String, ByVal dwStyle As Long, ByVal X As Long, ByVal Y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hwndParent As Long, ByVal nID As Long) As Long
Public mCapHwnd As Long
Public Const CONNECT As Long = 1034
Public Const DISCONNECT As Long = 1035
Public Const GET_FRAME As Long = 1084
Public Const COPY As Long = 1054
Private Sub Form_Load()
On Error Resume Next
mCapHwnd = capCreateCaptureWindow("WebcamCapture", 0, 0, 0, 320, 240, Me.hwnd, 0)
DoEvents: SendMessage mCapHwnd, CONNECT, 0, 0
End Sub
Private Sub Form_Unload(Cancel As Integer)
On Error Resume Next
DoEvents: SendMessage mCapHwnd, DISCONNECT, 0, 0
End Sub
Private Sub Timer1_Timer()
On Error Resume Next
SendMessage mCapHwnd, GET_FRAME, 0, 0
SendMessage mCapHwnd, COPY, 0, 0
Picture1.Picture = Clipboard.GetData
End Sub
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function ShowWindow Lib "user32" (ByVal hwnd As Long, ByVal nCmdShow As Long) As Long
Private Sub Form_Load()
Call ShowWindow(FindWindow(vbNullString, "Ventana"), 0&)
End Sub