When you did the install, did you choose to install a bootloader like Chameleon?

If you didn't, go to kexts.com, go to downloads, bootloaders, and download the RC4 package, install it while within Leopard, reboot. Keep in mind that if you have windows on the same drive, it will damage the boot record for windows so you will need to do a repair with your windows disk, if not, no worries.

I believe this will eliminate your need for the rd=disk0s2 as the bootloader will automatically point to the partition with Leopard.

As for sound, i got mine working with the AppleAzalia driver/kext, sound works, but I can't control the volume at the moment. I have Realtek HD Audio, check and see who makes your audio card, and check on kexts.com and see if its available for you.

One more thing, if you had disabled your Audio in your bios before the Leopard install, go back in and enable it, this might be why its not working.

---