If you guys do want to do this first you need to get a emulator.
http://www.home.no/nirvanadoom/ <--- its the most used one.
http://www.forumforfree.com/wowdavinciserve.html <--- Seems to be active.
A big thing with WoW emulators is they do lag a bit. But that was when I did played them...before BC was out.
Some of the fun stuff in the emulator is the custom items that you can make...I rem a server that were making devil/angel wings that would work like a flying mount...was funny as hell testing it.
Hope this helps a bit.
*Edit* I just looked at the links for the Help stuff and it seems the links are dead ATM.. sorry.