For detailed information on these hubs (and others) check the manufacturers websites
Sturmey Archer for lots of stuff from the archives and exploded diagrams of all their hubs.
Shimano for spares lists and options of fitting the Alfine to different frames.
Rohloff for a fantastic selection of stuff like internal animations and how it all works.
Tony Hadland's site has lots of stuff on rebuilding old Sturmey hubs.
Hubstripping.com is a new site dedicated to what's new in the wacky world of epicyclic gearing.
Sheldon Brown has lots of hub gear info and is probably the best place for Alfine info and a gear calculator.
If you prefer your info in printed form get hold of Tony Hadland's "The Sturmey-Archer Story" a fantastic book telling the tale of the history of Sturmey Archer and the birth of the cycle industry. Lots of hub info and tales of the decline of British industry, would make a great film.