LOOK UP/DETERMINE IF YOUR DOMAIN NAME IS REGISTERED
You can check world-wide to see if you domain name is available or to see if it has been registered yet by your registrant. Go to betterwhois.com. When the site appears you will see this, well actually more than this but I am only showing you what is necessary. Type the domain name you would like to check on in the box after the www. Then click on the SEARCH BUTTON.
If the name is already taken you will see a screen that shows the information below (using my domain name in the search box). On the left it shows that the name is not available and the page continues on (on the right side below) with information on the owner.
If you are using Yahoo! Domains (GeoCities Premium Service) you can go to betterwhois.com to see if the name has been registered yet.