VendorDA is a handy tool for people whose job is adminstrating or supporting other Macintosh users. It lists over 300 vendors of products for Macintosh, and includes manufacturers (O.E.M.'s), suppliers, and developers. It is certainly not the be-all and end-all of telephone lists, but rather hits the high spots, and lists most mainstream vendors (i.e., you won't find many little guys in it) -- this is because Display DA, which was used to create this desk accessory only supports 32K of data.
The list is a compilation of data from about six sources, including my own personal Rolodex, which has built up over the last three years into a cumbersome Hypercard stack, and is basically too much trouble to maintain. VendorDA is much handier, and quicker to call up when I need a number fast.
Hope you find it as useful as I do, and thanks to Bill Steinberg for creating Display DA. Cheers!