LARDY [Log Archiver and Rotator on DailY basis] is an easily configurable script used for archiving ANY application logs on daily basis with rotating capability and logging of the archiving itself. Also used for archiving on-the-fly [no loss of data].
Simple php database logging class with a simple front end to view logs. Allows fine grained tagging. You can also store data with each log and tag a log with as many tags as you need