URL Rewrite via function to parse out information from original URL

Hello, I seem to be getting close, but haven't yet seen an example of what I'm trying to do.  I've got a URL that looks something like this: 

http://mysite.com/Info.aspx?InfoID=4

The rewritten page should look something like this:

http://mysite.com/Info/thispage

I'd like to send the original url to a function that would parse out the InfoID, then do a SQL Server lookup for the "thispage" string to replace in the URL.  Can I do this via a simple function call that returns the resulting URL?  Can I also easily access the same page via the resulting URL (#2)?  For that I envisioned another function that would look up the correct page via a SQL string search on the page name.

I appreciate the help!