I don't know all the details, but it sounds like this is a pretty bad one. I don't have an axe to grind, and this isn't just some oddball tech website reporting the story. This is a really major flaw that's being reported in a lot of major news outlets. This is a big deal.
http://news.bbc.co.uk/2/hi/technology/7784908.stm
http://tech.yahoo.com/blogs/null/111811;_ylt=AqJLQ7r2VhquAHfYFHFXhYAazJV4
http://voices.washingtonpost.com/securityfix/2008/12/microsoft_big_secur...
http://www.abcnews.go.com/Technology/wireStory?id=6478928
If you use IE to do anything at all online (read email, shop, whatever), you really should stop as soon as possible. You are opening yourself to having your computer taken over by crackers, and no anti-virus software will save you. Simply visiting a specially-coded website is all it takes. No other browser is affected by this problem. Only IE. All versions of IE from IE 5 (ancient) to IE 8 (not yet released) are affected.
There are lots of good alternatives. http://www.getfirefox.com is one.
