Apple advisory - MacDefender malware will be removed by OSX patch
This is an interesting development and am hopeful they will be successful:
Apple advisory on "MacDefender" malware
QUOTE: Looks like Apple noticed that "MacDefender", a fake anti-virus tool that we covered earlier, is indeed starting to make inroads on the Mac user community. They have published an advisory today that describes how to "avoid" or "remove" the threat.
The advisory also states "In the coming days, Apple will deliver a Mac OS X software update that will automatically find and remove Mac Defender malware" which might turn out to be the first glimpse of an acknowledgment that yes, Macs can also have malware, and yes, Macs might even need a tool to remove malware.