I had seen a similar post that said a physical sound card was required in the ESX 3 server, but I've never tried this myself.

Paul

ESX doesn't support virtualizing sound hardware at all. In a previous thread, someone had mentioned they got this working in ESX 2.5 by editing the VMX file directly and adding in the sound card entries copied from a VMware Workstation VMX file, but that ESX3 broke this and wouldn't start the VM.

As far as I know, there's no way to add virtual sound hardware to an ESX VM at all. You might be able to use some sort of USB sound device over the network to a USBAnywhere device, but that's the closest thing to a solution I can think of. Otherwise I'm afraid you're SOL.