Users should ensure they are on the latest version of Quicktime and always be careful with email, IMs, and websites. 

New QuickTime exploit hits MySpace, steals passwords
http://www.f-secure.com/weblog/archives/archive-032007.html#00001144
http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=9013702

QUOTE: March 19, 2007  (Computerworld) -- A Trojan horse exploiting a flaw in Apple Inc.'s QuickTime that was patched two weeks ago is infecting MySpace.com users' computers, collecting confidential information, including passwords, several security companies said today. The attack is reminiscent of one late last year that plagued MySpace users and forced the popular social networking site to shut down hundreds of profiles.