This one sounds nasty .. glad I'm on UNIX.

http://www.techworld.com/security/news/ind...fm?newsid=12100

"Although it may not be clear how attackers are compromising such large numbers of websites, what happens after a site is infected is well-understood, researchers have said. When a visitor reaches one of the hacked sites, malicious JavaScript loads an IFRAME from a malware-hosting server; the IFRAME redirects the browser to a different page, also hosted on the hacker's server.

Next, a multiple-strike attack kit is downloaded to the visitor's PC. The kit tries eight different exploits, and if it finds one that works, hijacks the system. "

Another good reason to run Firefox with the NoScript addon. It blocks javascript and iframes.