As root, run alsaconf
to make sure your sound card is properly detected.
Then run alsamixer
to configure your settings; it's muted by default.
store to save the settings.
I cannot recommend pulseaudio. I have it on my Ubuntu laptop, and I have never encountered the audio problems with Slackware and ALSA that I encounter regularly with pulseaudio. I put up with it--what's an occasional reboot that takes fewer than two minutes?--because the computer has a Broadcom wireless chip and the wireless works. I've fought the Linux wireless wars before.
Even the pulseaudio website reports that pulse cannot yet be considered stable