If you know how made the sound card and the manufacturer, then you could also go here:
http://hardware.redhat.com/hcl/?pagename=hcl
Find your sound card and it's corresponding module, then run this as root:
/sbin/insmod "soundcardModule"
Where "soundcardModule" is the name of the module you found on RedHat's HCL page.
Now try "/sbin/lsmod" to see if it was loaded successfully. If it was, then try some sound applications like mpg321, xmms, and so on...