The sound should'ave worked out of the box, but it may be using a different output pin than what you have your speakers plugged into, so check your mixer and your connections. If that doesn't work, I suggest visiting the suse forums for a solution.
For the multimedia, I'd advise running the shell script here:
http://l2knet.awardspace.com/scripts.html
"PostInstall Peforms many post install tasks like adding install repositories, installing propriety software like Adobe Flash, Java, etc, and can set up a 3D desktop. "
It will give the options to add additional repositories, add support for missing multimedia codecs, install video drivers, install beryl, etc.