Microsoft just enabled the @live.xx signup! Go grab yours now! http://get.live.com/getlive/overview for the local domains (eg @live.co.uk) or use the following link for @live.com - @live.com signup.
So far the list of confirmed available aliases is:
Regarding the transition from @hotmail.com to @live.com, a pretty straightforward process is given on the new Windows Live site at http://www.windowslive.com/freshstart. Although you can automatically migrate your Hotmail inbox using TrueSwitch, anything else tied to your Live ID such as your contacts, Space, Xbox Live Gamercard etc cannot be automatically moved across due to legal and privacy issues. You can manually move across your contacts by exporting and importing into Windows Live Messenger, but unfortunately that's it. There's some useful tips if you do want to migrate though.