I think I answered this in your other thread already. Did my solution not work? Or did you not understand it?
Anyway, once again... Each of the .Net controls has an Anchor property that you can use to anchor it to the left, right, top, and bottom of the parent control or window.
So for instance if you take a multiline text box, anchor it to all sides of the window, as you size the window, the size of the text box will follow the size of the window...
You may have to play with the exact anchors you want to get the desired effect, but that's easy enough to do.
Edit: Just in case you can't find the property in the VB .Net form designer, here's the code that the form designer generates to set the Anchor property to be left, right, top, and bottom. Remove the ones you don't want anchored to get the effect you want:
Me.TextBox1.Anchor = CType((((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Bottom) _
Or System.Windows.Forms.AnchorStyles.Left) _
Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
*shiver* I can't believe I'm actually posting VB code. I feel so dirty...