How to watch synced movies on your iPhone?

I just got the DVD for Grease and synced the movie on my computer. Then, I went to my iPhone on iTunes and synced the movie on my phone. How do I access this movie on my phone?

First the movie has to be in.mp4, then you will find it in the "videos" app

I don't really know how…

If you sync the video that is in MPEG- 4 format, it will work.