Windows Live was announced yesterday. It is in Beta and seems to be and interesting concept for Microsoft. Windows Live is supposed to be e-mail, IM and other services (basically stuff Yahoo! has had working for ages) all via a web interface. Most folks are saying this is in response to Google.
Microsoft also announced Microsoft Office Live which is supposed to launch in early 2006. Basically it is an online business tool set. I don't know how successful it will be but it is an interesting idea.