Currently Being ModeratedApr 16, 2012 12:29 PM (in response to SFToy)
MPEG Streamclip can do this. If you don't have it already, you can find it here. I haven't done this in awhile but I recall the trick is to out both files, identically named before their extensions, into a folder and import the MPEG.
Currently Being ModeratedApr 16, 2012 2:29 PM (in response to Russ H)
You can do this with Quicktime 7 Pro:
Open each file in Quicktime 7 Pro:
Click on the audio file and do a Select All (Command+A) Copy (Command+C)
Click on the video file... Quicktime menu... Edit... Add to Movie...