codice:
Public Class Form1
    Public WithEvents msn As MessengerAPI.Messenger
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        msn = New MessengerAPI.Messenger
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim msncont As MessengerAPI.IMessengerContact
        Dim msnconts As MessengerAPI.IMessengerContacts
        msnconts = msn.MyContacts
        For Each msncont In msnconts
            ListBox1.Items.Add(msncont.SigninName)
        Next
    End Sub
End Class
Scusa se sono stato troppo poco generico