There is a great website called Screenwriting University. They have tons of free seminars and online help for writers in general, not just screen writers.
Today on their facebook page they posted a link to a new segment called How to writer a deeper scene, even if it is talking heads. by Hal Croasmun.
It is a really great piece. It breaks down the ending scene from Jerry Maguire and explains why it is such a great scene. I would suggest to everyone, not just screen writers that you take a look at it and listen to the suggestions.
So many times dialog scenes are just exposition, but these tips can help them be something more.
Thanx Hal for writing this piece and Screenwriting U for publishing it!