This is a difficult collision to answer. There are several types of collision. I would assume the type that you're looking for is sliding collision; however, that might be a large assumption.
I would recommend looking at the tutorial page for DBPro. I believe the Huge Dungeons has an example of very basic collision. My next suggestion would to be look for external DLLs such as Sparky's... if you use the Thread Subject Search you will find tons of information (well only a 100 at a time).
EDIT:
Sparky's is below... thanks... I really ought to save some of these links sometime or another.
If at first you dont succeed, LOWER YOUR STANDARDS.