I've heard a lot of claims that Macs are immune to viruses and spyware. From a programming standpoint I really don't understand how this is possible. Is it simply because Mac users are such a minority that no one writes spyware / viruses for them, or do they actually have some type of immunity. If so, please explain how it works.

It's mainly because of the fact the userbase is a minority. Some Mac fanatics do write virri fro the platform but, I've never heard of it causing a major problem to a lot of users. There just aren't that many users who want to exploit the system; the fact that the Mac OS is radically different Windows also poses another factor in why the system is ocnsidered 'immune'. It isn't immune at all, really, it's just that people probably don't bother writing virii for Mac OS in the first place because they know it'll be easier and much more devistating to infect a Windows platform. Afterall, let's face it, Windows has more security holes than the Mexico/USA border.

I was woundering this myself. I'm barrowing a imac from a friend that wants to sell it, I'm kinda trying it out. So there is NO virus scanners for mac's? I kinda like that as I spend hours a month on slow dialup download updates for virus scanners on my window$ pc.

There were viruses for OS 9 but I am not aware of any for OS X. Studying Information Technology at college and managing a Macintosh Specialist store in Utah should have exposed me to any information contrary to this. Two main reasons for this are the UNIX foundation which is quite dissimilar from the Windows-DOS based format and the security implementations from Apple engineers. Not to say that there won't be one in the future but when Microsoft has to spend all their collective brain power creating a 300MB service pack to fix all their problems, is it no wonder that Windows Vista has been delayed for over two years now?