Hi,
gMote for Windows :
http://www.handform.net/gmote.php
I've used this for ages to add mousgestures to windows. It works in WoW too.
I've also had some success using it in wow. It works ok but it wasn't responsive enough for me, during combat, on my relativley old pc. (2.6GHz Athlon + 3Gb Ram - top of range 5 years ago :P )
Give it a try - you may have more luck than I did.
edit:
I assume you're a windows user. Linux has mouse gestures module freely available. I'm not sure about Mac.