http://www.mplayerhq.hu/homepage/design7/dload.html
go there, download source and essential codecs
tar xjvf the codecs file and as root mkdir /usr/local/lib/codecs
then move the contents of the codecs file in that newly created codecs directory
then extract the mplayer file and cd into its directory, then run ./configure, if all goes well, then run make, and as root make install, poof, youve got mplayer.