It can be done, but it isn't pretty. First, you have to intercept the mouse event message WM_NCLBUTTONUP from the non-client area (e.g. the title bar) then check the position of the window being dragged and re-set the top and left properties. You have to create your own message loop to intercept the message because the default event procedures given by VB for a form don't include non-client area events.
If you don't know what I'm talking about, or don't know how to intercept messages, then you have quite a bit of reading to do. Here's a link to a VERY short introduction of how to do this: http://www.garybeene.com/code/visual%20basic30.htm Read it, and if it still doesn't make sense then you should think again about whether you want to implement the functionality.
Apparently there is a problem trying to use the WM_NCLBUTTONUP message... there is a workaround if you decide to do this. Look at this URL, near the bottom under "Community Content": http://msdn.microsoft.com/en-us/library/ms645621(v=vs.85).aspx