ForaTV has Ken Burns in Conversation with Robert Stone from The New York Public Library. Burn talks about how Steve Jobs roped him into the association with the effect for iLife; see time 1:33:30 in the video embed. [see another interview at the Archive of Television]
For more, see Poynter Online's advice on Burns and His 'Effect' and background in Wikipedia.
By the way Noise Industries is still offering a free FxPlug, Fxfactory pan and zoom plug-in (Mac). There are numerous tutorials for this effect if you don't have a plug-in. Shane Ross did a video tutorial for FCP at Creative Cow. In the Adobe world, this sort of pan & scan is done by Anchor Point animation; see Chris and Trish Meyer's article on pan & scan at Artbeats and More Motion, Less Control (on adding a human touch) at PVC for good results.
Examples of taking the effect to the next level are also numerous, especially after the movie The Kid Stays in the Picture, noted in another article by Trish & Chris at Artbeats. There's also Bob Donlon's example in Son of Ken Burns, a Richard Harrington video in 'Motion Control' with After Effects, and other AEP resources for multiplane animation.
Update: here's more on multiplane cameras from an old Disney show (filmed: Feb 13, 1957):