That is another probably good place to ask questions, but here's a few places to find answers:
mod_rewrite Cheat Sheet - Cheat Sheets - ILoveJackDaniels.com
Easy Mod Rewrite : mod_rewrite tutorial
mod_rewrite: A Beginner's Guide to URL Rewriting [Apache & IIS Configuration]

I can give you a hint too, you're going to want to use a RewriteCond for the first one you want to do, and a relatively easy RewriteRule for the second. It's possible to have almost as many rules as you want, though it is easy to run into conflicts. The rules cascade though, so it'll go through them one by one in order until it finds one that matches.
-m