Hello MobileMe, goodbye .Mac (and good riddance). Apple's synchronization and web application solution for your Macs, PCs, iPod touch or iPhone is now live. Push eMail, push contacts, and push calendar and a new suite of web applications are now yours for the taking. You know, after you hand over $99 for the first year or $149 for a one-year family subscription.
P.S. Things are loading slowly at the moment as the service comes up.
Update: As noted in the comments, the site is now down for most people.
Update 2: It's coming up again but it's still flaky as hell. We've managed to get to our calendar, contacts, and settings but Mail is still a no, no.