This is a fun site! The recordings range from about 1902 to about 1919. You can listen to speeches by Presidents Theodore Roosevelt and William H. Taft or hear a rare recording by Edison himself (he didn't like to have his voice recorded!). Musically, there are pieces from just about every genre you can think of. There are national anthems of various countries and there is a section called "ethnic humor" [this section contains bits by humorists of various ethnicities--here's a sample of Scottish humor from 1908].
Cylinder recordings, the first commercially produced sound recordings, are a snapshot of musical and popular culture in the decades around the turn of the 20th century. They have long held the fascination of collectors and have presented challenges for playback and preservation by archives and collectors alike.
With funding from the Institute of Museum and Library Services, the UCSB Libraries have created a digital collection of nearly 7,000 cylinder recordings held by the Department of Special Collections. In an effort to bring these recordings to a wider audience, they can be freely downloaded or streamed online.
And, if you're interested, check out the copyright situation.