While looking at the kludge called MSP (MUD Sound Protocol) and the slightly better but still klunky MXP (MUD eXtensions Protocol) and the zMUD support for MSP, I wondered, where do you find the sounds to go with it? Is everyone using old 8-bit .wav-files from ancient times, or stealing of the CD for Dark Ages of Camelot?

I think MSP uses wave files. Not entirely sure though.

If you read the spec's for 0.3 You can also add a url tag so that if you find a cool sound somewhere on the web you can just point it to that url or add it to your web server for players to use. That doesn't answer you question. However I'm planning on using it in our mud and basicly ask the players what sounds they would like to hear and for what actions. think of what sound you want, i.e. death cry. and then seach the web for a cool death cry wave. MSP also allows for music files and such, could be interesting with a bard class or just really annoying.

I have indeed read the specs. Unfortunately, the zMUD users I have spoken to who have tried to use URLs to the sounds have reported that zMUD crashes when they try to...

But URL specs means you will be downloading the sound. On the lagged internet (server pushed commercials, anyone?), that means you'll get the sound played too late. Then, you need caching -- and that is basically downloading in advance. This leads back to my original question: where can one find sound files, preferably in 16-bit wav format?