I am a pretty skilled programmer, but when it comes to RegEx and rewriting, I am a total n00b. I want to convert a URL from
http://www.example.com/lookup.ph
Do you want to redirect from the old URL to the new? Or are you looking to read in those "friendly" URLs and then have them behave like the old URL?
If it's the latter, try taking a look at Net_URL_Mapper as a way to parse and redirect those links fairly easily.