I disagree with Joe Offer - CD (or DVD) is a perfectly acceptable medium for archiving, provided you don't assume that it is forever and plan to re-transfer to another medium after a reasonable number of years. This could even be CD or DVD again, or whtever has replaced them by then, because they are so cheap, so cost need never be an issue.

I'd also like to reiterate the warning against MP3s for the reasons already stated. WAV of 44KHz should be the format.

But equally important to all that it indexing. Think about it. With the proliferation of cheap recording media, every man and his dog is archiving stuff for posterity. Much of it is crap, meaningful only to the archivist. Fifty years from now, when the creators of the archives have gone on to learn the harp in the Great Ceilidh, who will listen to all that stuff? We are talking information overload here, and a good, clear index using as standard a method and toold as possible would be invaluable for the inheritors of the "treasure" and for any researchers.

Open mike, as you are setting up a studio to provide an archiving service, you might also want to back this up with an indexing capability.

In any case - make sure those that follow can sort out the jumble of sounds you are archiving by providing them with an index. They'll be lighting a candle for you rather than curse you, if you do this.