tangor - 9:40 pm on Mar 26, 2010 (gmt 0)
If the Mac was not vulnerable why would the major virus protection companies write software for the Mac? From a dev company point of view those r&d resources could be better expended elsewhere than creating software for a "non-vulnerable" OS.
Malware is written for the installed market...and at this time that is PC. There are Mac virii out there, and more coming each day... because the malware authors have realized that Mac fanbois have more money and less exposure to their tricks simply because those users aren't used to them... yet!