harry fuecks does a good job at explaining mvc. so if you didn't already, go on and read it.
http://www.phppatterns.com/index.php...leview/19/1/1/

you won't see a lot of explanation on the model in theese mvc-discussions. that's because it's really outside the scope of mvc. basically mvc is about control-flow in your application.

about modrewrite : http://www.sitepoint.com/article/910/