PSA of the Day: Conficker worm scheduled for activation April 1st--April Fool's joke or real threat?
Per this post by Tina at The Agonist, Microsoft thinks it's a real threat and is offering reward for finding author, etc. It has gone through several very sophisticated versions.
Commenter graham posts NYTimes article snippets and link for Enigma's free detector/removal tool.
I am not a expert in this stuff, but seems worth checking out.