I'm assuming you're running wine, not cedega?
Well anyway, try putting/editing this in your Config.WTF (/path/to/World of Warcraft/WTF):
Code:
SET SoundBufferSize "xxx"
It's pointed
here for a different problem, but it basically determines the lag between game and sound. It can take a bit of fiddeling to get perfect though.
Mine's set to 85.
GL
-nfsnobody