At some point within the last week, some MySpace user pages were seeded with malicious computer code. The malicious code seeks to exploit Microsoft Windows and Internet Explorer using recently patched security holes. The hope is that you haven't patched your computer yet. If you're a MySpace visitor and you visit one of the infected pages, you'll be redirected to a fake MySpace log-in page aiming to steal the visitor's MySpace user name and password. The attack employs phishing and drive-by download techniques.
SANS' Internet Storm Center offers a detailed breakdown of the attack.