The first thing you should do is find out what type of sound card you have, once you know that you can start doing more directed attempts to make it work.Assuming you're running x86 with on-board sound you'll probably succeed if you run, as root, this:

apt-get install lspci
lspci -v -v

The first command installs the "lspci" package, which will allow you to see what is connected to your PCI bus.

The second command uses the newly installed tool to output whatever it can.

When I run this upon my host, for example, I see this output:

skx@itchy:~$ lspci -v -v | grep -i audio
0000:00:02.7 Multimedia audio controller: Silicon Integrated Systems [SiS] Sound Controller (rev a0)

This tells me I'm using some kind of SiS audio card. For me running "modprobe i810_audio" gets it working - but you might need to use another module.

I would guess that you won't need to recompile your kernel yourself if you're using the Debian supplied one, since that has modules for almost all the common hardware already enabled.

Steve