[Cleo]

There are other players besides quicktime that will play mp4 movies.
Here is a list of some of them. I haven't actually used any of them.
http://www.divx-digest.com/software/...r_classic.html
http://www.leadcodecs.com/Codecs/LEAD-H264.htm
http://www.mplayerhq.hu/design7/info.html
http://www.free-codecs.com/download/...Codec_Pack.htm
http://www.videolan.org/vlc/
http://www.elecard.com/products/prod...r/mpeg-player/
http://filehippo.com/download_quicktime_alternative/

There are also a bunch more listed over here.
http://forum.doom9.org/showthread.php?t=95939

Also here is a plugin for WMP that claims to allow WMP to play H.264 vids
http://www.wmplugins.com/ItemDetail.aspx?ItemID=1129