I got sound to work. I had to download DOS Soundblaster drivers, and run everything in pure MS-DOS (I have Win98) and it worked. Oh, and you'll probably have to make a boot disk too. I'm not sure about XP though.
"You boldly enter our space! Approach this Dreadnought as though it were a recreation base and then play the dumb hominid? Who do you take us for, Captain... Spathi!?"
I've tried the most recent release of Dosbox on WinXP, and managed to get both Star Control and Star Control II to work with sound. There has been a little skipping in SC2, but other than that they both work. I had to use the /g:bios switch with SC2 to get the screen colors to stay correct.