The latest issue of ipFrontline has an interesting article called "The PTO's Document Disclosure Program: Boon or Boondoggle," by former patent examiner Thomas G. Field.
The USPTO is currently seeking public comment on a proposal to eliminate the program. See the Federal Register April 6, 2006, vol. 71, p. 17399. This is the third time since 1998 that the agency has proposed eliminating the 27-year old program.
USPTO's Disclosure Document Program brochure.