How do I import into iTunes a MPEG-4 Movie I have made?

Make sure the MPEG-4 file extension is ".m4v".

WARNING: If you're unsure how to do it, don't change it!

Just make sure that when you're encoding your MPEG-4 file, it's saving it with the extension ".m4v". iTunes and some iPhone/iPods have problems with other video file extensions, it can sometimes be hit and miss. But ".m4v" works with little/no problems.

If you open the file using iTunes it will run the video from it's current location and automatically add it to iTunes.