Reporting data in PHP

Has anyone got a good reporting library for PHP/MySQL based sites?

I'm working on songoftheelves.com and I'm tracking downloads of chapters to get some stats on who's downloading what and when.

I wanted to present these stats in a nice table and be able to drive the table as to group the results arbitrarily by time, date, which chapter and/or user. Googling for a library to do this didn't turn up anything useful immediately, so I'm throwing one together, not MySQL specific, able to be driven by an arbitrary data source (MySQL, an array, XML feed, etc).

If anyone wants to save me from re-inventing the wheel and point me in the direction of something similar, that would be much appreciated! This must be a commonly encountered problem, so there must be a pre-existing solution out there somewhere. If not, there will be soon.