Free
Windows Live ID (Formerly known as Passport) is a single sign-on service offered by Microsoft. Setting up a Windows Live ID allows you to access several different applications with the same credentials. Some applications that use your Windows Live ID to authenticate you include Hotmail, Windows Live Messenger, and MSN. Xbox Live also uses your Windows Live ID! If there were no Windows Live ID service in place, you would need a separate ID and Password to access each of these services.
Do you mean a Windows Live ID?
Yes.
Yes, Windows Live Messenger is a free program.
No
Windows live messenger is free to everyone. It has nothing to do with your mobile network.
No u cant
You cant :P
There is no charge to have an account with windows live. Windows Live is a free email service, in which a free account is set up, that can also be used with Windows Messenger and Microsoft accounts.
U have to contact xbox live support
yes but it costs 800 Microsoft points
Unfortunately you cannot change your windows live id. If you get it wrong or want to change it you need to create a new account with accurate details.