London-based electromechical technology museum: they collect and restore things like generator sets and lifts. I came here via the excellent section on Compton church organs (the British equivalent of Hammond, using interestingly different technology).
Detailed instructions on oiling various Hammonds, with pictures. This was useful to see what my L-100 was *meant* to look like inside when reassembling it.
Manuals for all the Leslie hookup kits, past and present. Most of these have schematics. This was invaluable when connecting my Hammond L-100 (circa 1965) and Leslie 2101 (circa 2005) -- Suzuki T/A Hammond do make a kit for that, and the schematic's here...
Everything you could possibly want to know about Leslie speakers: pinouts, schematics, comprehensive model lists, etc. etc.
Hammond maintenance tips -- specifically on oiling.
A nice collection of modifications for the L-100 series. I'm quite tempted to do the in-phase chorus mod on mine...
German Hammond technician. This has some interesting mods for the T-200 series, which are effectively transistorised versions of the L-100 -- e.g. adding a valve distortion unit based on Russian miniature valves. I also like his tonewheel level calibration software...
The drawbar/percussion settings for "A Whiter Shade of Pale".
Modifying a Hammond M-100 series spinet organ to behave more like a B-3.