I did finally get my sound working on my Dell 1521 by following these instructions at https://help.ubuntu.com/community/HdaIntelSoundHowto
I am running Kubuntu 7.04 with the 2.6.20-15-generic kernel. After I got the sound working I updated to the 2.6.20-16-generic and it broke my sound again. I suppose I could recompile ALSA but for now I am just going to keep running the older kernel. This Dell sound stuff seems to be very picky and now that I have it working, I don't want to mess with it.