Quote
It is possible, Cleglaw !

Open the file "realmlist.wtf" in your favorite editor (you should found this file in c:\program files\world of warcraft) and change the one line to

Code
set realmlist eu.logon.worldofwarcraft.com


your should be

Code
set realmlist us.logon.worldofwarcraft.com


or similar.

Thank you. How can I do it so that I can log into either the US or Europe?

The question is not, Can they reason? nor, Can they talk? but, Can they suffer?
~Jeremy Bentham