W32.pipeline worm strikes AIM

A sneaky new worm has appeared on the scene.  The attack starts as an instant message from a friend asking "Hey would it be ok if I upload a picture of you to my blog?"  The text is actually a link which downloads a file and installs itself on the hapless user's machine.  There's been a lot about it in the press today, but the best account is on blog.spywareguide.com.