The next generation
Windows Live Messenger 8, formerly known as MSN Messenger, has been released to beta testers. I've downloaded and installed it, and I like the little changes to the interface.

I'll be posted a full-fledged review later, but for now, a few initial observations.
- The beta is not open to the public. It is open to the "Beta Butterflies" (previously registered beta testers) and new beta testers by invitation. Any current beta tester can give you an invitation.
- Want an invitation? Add your name to the list.
- I've also posted some screenshots on Flickr.
- It works through my corporate firewall (MSN Messenger 7.5 did not).
- Favorite feature? So far, the integration of the full menus in "frameless" mode, similar to Windows Media Player 10.
- Product Manager Leah has posted the official feature list on Inside Windows Live Messenger, the development team's blog.
I don't like the Windows Live moniker (what does this mean for Mac users), but I generally like the direction of the new version.