2 videos with different frame rate sync problem

[dgiulian]

Hi everyone,
I have a mkv file with a movie (it's The Lion King, i'm not affraid to say it) ripped in 720p, but the problem is that the audio is in english, but I wan't to have the audio in Spanish.
I also have the same movie, but with less quality and the spanish audio.
So what I wan't to do is to take the audio from the bad quality movie, and append it to the mkv file to have a dual audio avi file (I will do it with avimux).
But here is my problem, the 720p version is a little bit faster than the other, I don`t know if this has something to do with the Frame rate. The first one is in 24,5 fps and the other is in 29,5 fps.
I converted the latin version from 29,5 to 24,5 fps, hoping that this would fix the speed problem, but it didn't.
So here's my question, how can I sync both videos?

[davexnet]

Usually the PAL version is 4% faster than the NTSC version due to the 24 > 25 frames per second speedup.
In the past I've used an audio editor with a timestretch function (Audacity or similar) to stetch the audio to the correct time.