#1 - June 10, 2009, 7:34 p.m.
It sounds like you may have accidentally stumbled upon the part of account management used for adding legacy games to your Battle.net account such Starcraft, or Warcraft III. Fortunately, you will not need to verify the authentication keys for World of Warcraft when merging it with your Battle.net account.
The following link should bring you to the correct page for adding a World of Warcraft account:
https://us.battle.net/account/management/wow-account-conversion.xml
Please let me know if you experience any further issues.