Ok first make an account on one of the wow trading websites or a wow forum website.
Make a post claiming you are renting other peoples accounts for money, gold, leveling etc (be creative). Direct them to your msn address for further info etc.
Now most people use the same msn address as they do for wow. They also quite often use the same password.
Say you are renting their account etc etc. Now get their account details password etc. Now go on hotmail etc and check if they are using the same password for wow and hotmail. If so you're in luck. Change their wow and hotmail passwords.
You now own their account
XxX
Have fun flaming cause then at least reading this was worth it ^^