Interesting story over on ZDNET (I originally sourced this on Slashdot) about Apple MAC's and what's being called iBotnet ...

MAC's may be so crippled that they don't get turned over by web based drive-bys, but they are not invunlerable to the invasion of the botnets!

What's even funnier about this is that if you are a part of this botnet, the chances are high that you pirating some dodgy MAC software from a P2P network! haha talk about being exposed!

http://blogs.zdnet.com/security/?p=3157

Read the complete post at http://wmug.co.uk/blogs/r0b/archive/2009/04/17/got-a-mac-are-you-part-of-the-ibotnet-only-if-you-are-a-dodgy-pirate.aspx