A clean vanilla OpenSUSE install comes with a lot of tools for all kinds of tasks. Some things, however, are not available. Notably, this includes potentially patent-infringing software, i.e. software which plays mp3, dvds, wmv etc. These are omitted to eliminate the risk of legal action.
A system that does not play mp3s is not much fun, so one of the first steps after installing OpenSUSE is to add all the missing codecs and software. A great place to go for tips on getting codecs, binary-only drivers and browser plugins installed is the Jem Report, a blog by Jem Matzan. Just follow his steps. If you installed with the extra OpenSUSE CD containing non-open source packages, you probably already have Java, Flash, RealPlayer and Acrobat installed, so you may skip those sections.
Once you have installed the codecs, your audio and video players should be able to handle mp3, wma etc. Kaffeine is a good video player, and amaroK is a cool audio player. Both are available on the OpenSUSE CDs/DVD.