This is the article, but the most important thing to remember is:
Most of the worms were using onmouseover techniques, meaning it was enough to move your mouse on top of a malicious Tweet to resend the malicious message to your followers.
http://www.f-secure.com/weblog/archives/00002034.htmlTo protect yourself:
log out of Twitter
Use client programs to access Twitter instead of using twitter.com
Turn off Javascript
