Apple's List of Software Incompatible With Snow Leopard
While it's impossible for Apple to test every application and hardware device with its OS, the company has posted a list of software that it knows to be incompatible with the 10.6 update. The big names include Parallels Desktop and Norton AntiVirus, though even Apple's own Airport Admin Utility for Graphite and Snow makes the list.
If you're thinking about jumping on the Snow Leopard bandwagon, we suggest you check the official sites for any critical software you use before doing so to look for any potential issues. It might also be helpful to check various Apple forums for user-generated lists of incompatible software, like this one from popular Apple site MacRumors. [From: TUAW]