Unlike as in VB6, where you have to use the API to create a translucent or transparent form, you only need one line of code to do so in VB.NET. Specifically, all you have to do is set the opacity property of the form to the desired value.
Private Sub Form1_Load(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles MyBase.Load
Me.Opacity = 0.5