I gather Amazon’s CreateSpace operation has been around for awhile, but I only just discovered it. I am amazed. Through CreateSpace you can not only create books, audio CDs, DVDs, and audio and video downloads, but for a royalty you can also offer them for sale through both CreateSpace and Amazon.
The prices are the lowest I’ve seen for on-demand book printing, and with the fewest restrictions. And for audio CD replication (i.e. in quantities 1,000 or greater) the price is not the absolute lowest, but pretty close.
These guys are definitely my first choice now for book publishing, and I’ll be looking more closely at them for CDs as well.