According to the Microsoft Internet Explorer Weblog Microsoft are going to release another version of IE for XP users. This is contrary to what was issued before, stating that to use IE7 you'd have to buy Longhorn; Microsoft's up coming sequel to XP. Reports state that we can expect betas of IE7 in the "summer".
Blake Ross who featured on the cover of Wired magazine for Firefox last month has a good timeline of the Microsoft U-Turn. There is also a good article over at Mozillazine about this announcement. A quick search on Google News for Internet Explorer will bring you a wealth of information on this exciting news.
I can't wait! This is great news!