Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        Me.TabControl1.TabPages.Add("Neues Tab")
        Dim w As New WebBrowser
        w.Dock = DockStyle.Fill
        w.Navigate("http://www.google.ch")
        Me.TabControl1.TabPages(2).Controls.Add(w)
    End Sub

fg viperbone