We have just launched a new site, Gamertag.world, where you can check availability of Xbox Gamertags, should you wish to change your handle or sign up for a fresh account.
All you need to do is enter the Gamertag you wish to check, and the site will let you know whether it is currently available or already claimed. Once you find a Gamertag you’re happy with, you’re all set to either change your Xbox name or sign up for a new account. The site also has an FAQ page that tells you everything you need to know about Xbox Gamertags and how to change them, so be sure stop by if you run into any issues.