About how long? I didn't hear about it unil a few months ago.
Found it about three years or so back.
The description says,"a total of 1337 shows from December 1992 until November 2013" and it has extras like an audio book of "The Art of Talk", After Dark newsletters from 1995, some Phil Hendrie parodies of Art and so on.
Bart prefers no links on this one due to copyright violation, so how you search it out is up to you.