Heya, Markus.
MDB2 is the preferred package among PEAR aficionados (
http://pear.php.net/package/MDB2).
I generally prefer to roll my own. I recently wrote one for MySQLi, though I hardly consider it anywhere near complete. I'll post it in a second; it's... well, you'll see. My code is always well-documented (:
[EDIT: Posted. It probably won't work outside of the framework that it is a part of, but it should give you a pretty good idea of what's going on inside my head. Post back if you have any questions.]