Converting from .mkv to .avi to .mp4?

OK, so I have these .mkv video files that I want to watch on my iPod Touch. Now obviously, I need to convert these into .mp4 files. Unfortunately, it takes FOREVER to convert a .mkv file into .mp4.
I've been told by a friend that I can basically "take apart" the .mkv file, seperating the audio, video, and text files. According to him, I can then put them together as an .avi file and from there, I can convert into .mp4. Is this possible? And if so, how long is the process?

What are your computer specs?
They make a HUGE difference!

Just incase, .mkv
http://www.fileinfo.net/extension/mkv

What converter are you using?

http://www.videohelp.com/tools/MKVtoolnix

Install MKVtoolnix and then download MKVExtractGUI and extract into the MKVtoolnix directory.

MKVextractGUI.exe will enable you to load and split out the files (video, audio, and subtitles) making up the mkv file.