SANS: New Mac malware - OSX/Onionspy
Yes, as Macs become more popular, malware is going to be written for them. Two more things that make this even more interesting is in the comments of this SANS Diary article. #1) it would seem to detect and remove it you have to buy the anti-virus software of the company that discovered the malware. #2) the last comment seems to indicate that the makers of the malware have read the SANS Diary article and are stating that more malware for Macs is going to be released soon. Not trying to spread rumors, fear or panic, but maybe its about time to start investing in anti-virus for your Mac.