You imply with your title that there's a new virus in town specifically targeting Macs. What you don't say is:
- Trojan horses are *not* viruses -- viruses replicate on their own. To get this trojan horse, you had to download a hacked copy of iWork '09 off a pirate website and install it.
- This thing's been around for months, it was discovered in January.
Bottom line, Mac-using family and friends -- don't go to pirate sites, free mp3 sites, or any porn sites. If you stay away from those, you're still pretty safe using a Mac.
Oh, and watch out for FoxNews, too. =)