The trojan, named "iBotnet" (get it?), has only affected a few thousand Macs in the wild and it is currently not known to do any real harm. Should you be concerned? Well, the answer to that depends on whether you're a software pirate or not. The distribution method for this particular piece of malware is through the downloading of certain bootlegged copies of Apple's iWork.
Brian Krebs over at the Washington Post details some information about the actual first botnet specifically for the Mac. He points out that the current media storm is for a trojan that was actually discovered in January. He goes on to mention that the first botnet for the Mac was actually released in 2006 and targeted both Macs and PCs alike.
In other news, sales of Symantec's Norton AntiVirus shot up following the release of the security bulletin and subsequent frenzy of coverage. Actually, this is not true (at least to this humble blogger's knowledge); but it does pose an interesting question. Who profits most from the release of malware on any platform? One thing we know for sure, though, is that the end-user is definitely losing out in this game.
The moral of this story: stop all the downloading! Thanks G.I. Joe! In all seriousness, though, the majority of malware on the Mac (and on the PC) is distributed through nefarious chains of content acquisition. Be careful out there when clicking links and downloading files or programs from sites that you may not trust.
Thanks to everyone who sent this in!