Quick and dirty for installing your multimedia codecs on your newly installed ubuntu (7.04) system.

From the command line run

$sudo aptitude install gstreamer0.10-pitfdll gstreamer0.10-ffmpeg gstreamer0.10-gl gstreamer0.10-plugins-base gstreamer0.10-plugins-good gstreamer0.10-plugins-bad gstreamer0.10-plugins-bad-multiverse gstreamer0.10-plugins-ugly gstreamer0.10-plugins-ugly-multiverse libxine-extracodecs w32codecs

(just copy and paste the above string)

This should get you up to speed with the most commonly used codecs.

-j