Using mod_rewrite with PHP

I've been wrestling with mod_rewrite and trying to understand how to use it for my particular purpose. I've got two php URLs I'd like to rewrite to make them search-engine friendly. Currently they look like: Example 1: http://mysite.com/foobar.html?c=23 Example 2: http://mysite.com/foobar.html?c=23&p=45 What I'd like to end up with is something like: Example 1: http://mysite.com/foobar/23 Example 2: http://mysite.com/foobar/23/45 I'm kind of new to mod_rewrite and regexp's, so can anybody give me a clue? Thanks! Gawain