theres two options, mplayer or xine... i prefer mplayer.. go to http://www.mplayerhq.hu/homepage/design6/dload.html
and download one of the source files... To install:
1)go to your CLI (Command Line Interface) which should be konsole, xterm or something like that
2)go to the directory using this syntax | cd <dir> | cd .. (goto previous directory) and use the command ls to view whats in your current directory
3)type tar -zxvf "filename"
4)it will create a folder, cd into that folder
7)type su and enter password for r00t
8)type make install
now in the command line, there should be a command mplayer, have fun!