https://en.nostalrius.org/ - Click How to Play tab, register your account, check mail for confirmation mail if one should be sent, can't remember if I had to do it, but some services require you to activate your account through a link sent to your registered email.
Also, you mention realmlist in your WTF folder (I suppose you mean inside the config file?) either way, you should change it in the realmlist.txt file in the general World of Warcraft directory as well.
