Fixing audio sync on avis, mpegs

[stultus]

I download a lot of stuff from newsgroups (like foreign TV rips) and it seems like TV rips are pretty hit-or-miss on getting the audio sync correct. Is there a simple program where I can rework this, or, better yet to adjust on the fly? A lot of progs will be pretty good, but then coming out of a commercial the audio sync will be off.