Technically, the mechanism in skwire's old Atari drive is probably no different from a normal 5.25" mechanism, (most likely Double Density), the only difference being external interface circuitry. It should just be a matter of removing the drive from the case/interface and plugging it into a a 'normal' interface. This was the case with the floppy drives for the Amiga and Vic20 computers, standard 5.25" drive with external interface.
Though you will probably have to find a motherboard that still has a floppy interface and a cable that most likely will be the old PCB edge connector.
I used to use floppy drives from MS-DOS/Windows based machines on the Amiga, a little interface board took care of the extra signal and drive ident that the Amiga required. Only exception to this was Amiga HD floppy drive which ran at half speed because the controller inside the Amiga couldn't handle the faster data rate of normal rotational speed.
You also need to know whether the disk is DD or HD, obviously the HD can't be read in a DD drive.
(Wow, cheapest 5.25" on ebay atm is a HD @ AU$55 + P&P)