It may not be Windows Mobile Device Center, but at least it's somthing: ActiveSync 4.5 has been released today. Doesn't look like there's anything new here that wasn't in the Beta, though. The biggest feature to 4.5 is faster file transfer speeds. The second biggest, ah, "feature" is that Remote PC Sync has been removed because it was just to difficult to keep secure. I've been using 4.5 Beta for awhile and I'm content with it.

Download details: ActiveSync 4.5 (thanks to msmobilenews for the ip)