Problem viewing saved movie

I have captured video from my Camcorder, created a movie and then attempted
to save it to my computer. When I view the video using Windows Media player
the video color is all distorted. It almost appears like a Tie-Die with many
unusual colors. I can play the video using Nero, but not with Windows Media.
Anyone know why?
Also, What format is best for saving small movies for emailing to friends?
What format is best for highest quality video for playback to tape?

Thanks! Thanks! Thanks in advance.