That doesn’t mean you can’t play .mp3 files in Ubuntu 10.04 LTS (Lucid Lynx), it just takes a bit of work (not much).
Follow these instructions to get mp3 and other multimedia support on your Ubuntu 10.04 LTS (Lucid Lynx).
$ sudo wget --output-document=/etc/apt/sources.list.d/medibuntu.list http://www.medibuntu.org/sources.list.d/$(lsb_release -cs).listAfter adding the repositories, install the codecs:
$ sudo apt-get --quiet update
$ sudo apt-get --yes --quiet --allow-unauthenticated install medibuntu-keyring
$ sudo apt-get --quiet update
Install non-free-codecs:
$ sudo apt-get install non-free-codecsInstall DVD Support by using following command:
$ sudo apt-get install libdvdcss2Windows codecs:
sudo apt-get install w32codecsVLC player and Mplayer:
$ sudo apt-get install vlc mplayerAdobe Acrobat Reader
$sudo apt-get install acroread acroread-plugins
source:http://linuxpoison.blogspot.com/2010/05/135781677511700.html