The Logitech Control Center (LCC) is the name of the driver software for Logitech mice and keyboards. The latest versions still have issues with Snow Leopard; here are a couple of semi-workarounds for some of those issues:
LCC version 3.1:
This version creates weird tabs in Safari if you have a few Safari plug-ins installed. The solution is to remove the /Library » ScriptingAdditions » LCC Scroll Enhancer Loader.osax package and reboot.
LCC version 3.2:
Your mouse pointer may suddenly jump to some other part of the screen, every other minute, making it almost unusable! A lot of people are complaining about it, but still no fix from Logitech. The Logitech 'solution' is to downgrade to version 3.1: uninstall 3.2, reboot, download 3.1 from the Logitech FTP site, install it, reboot again.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20100322143728329