By default, Ubuntu (and many Linux distributions) cannot play MP3 audio files. This is because of copyright laws (makes it a restricted format) which prevents MP3 functionality from being bundled with Linux distributions.
This does not mean you cannot play MP3 audio files on Ubuntu, it just means you need to download an encoder first.
We'll search (using Synaptic or just a console) this 2 packages:
ffmpeg - multimedia player, server and encoder
gstreamer0.10-ffmpeg - FFmpeg plugin for GStreamer
Searching the packaches using a console:
flaca@anneke:~$ apt-cache search ffmpeg
flaca@anneke:~$ apt-cache search gstreamer
We'll install the packages using a console:
flaca@anneke:~$ sudo apt-get install ffmpeg
flaca@anneke:~$ sudo apt-get install gstreamer0.10-ffmpeg
Once everything is installed on your computer, you're ready to listen your mp3 audio files :)
Hope it helps.
Enjoy your music and Stay Heavy \m/