VLC is a free and open source cross-platform multimedia player and framework, that plays most multimedia files as well as DVD, Audio CD, VCD, and various streaming protocols.
To install VLC 1.1.1 open a Terminal window (Applications -> Accessories -> Terminal) and copy+paste the following lines:
sudo add-apt-repository ppa:c-korn/vlc && sudo apt-get update
sudo apt-get install vlc
sudo apt-get upgrade
When installed you can find VLC under Applications -> Sound & Video
If you already have the c-korn ppa and VLC installed all you have to copy is: sudo apt-get upgrade