Best way to get sound in sync

[Slogra]

I made an avi but the sound is not perfectly in sync... what's the easiest/best way to get it right? (i coulnd't find it in the faq)

[Slogra]

Oops, i forgot to mention info about the avi. It's Divx4 and Lame ABR 112 mp3 audio.

At this moment I just put a (guessed) delay in Nandub and check if the sound is in sync, but i'm sure there is a much better way.