I have a fairly new Dell PC at work and Ubunto 5.04 needed some poking to work right. The sound card was one of them. In my case, it was an Intel AC97 chip, but the kernel driver doesn't know the PCI IDs. What I did was get the kernel source package, add the PCI IDs to the intel_snd8x0 driver, compile it, and bung it in the modules directory. This did require a few cycles trying to get the version extra string correct, BTW, in the kernel config.
Wade.