1) Nothing but a cable
2) Yes
3) The non-Apple equipment will work just fine. Apple's base station is perhaps slightly more seemless and you should definitely get it if you need to use Appletalk on your network (I need Appletalk to communicate with my old Laserwriter IIg printer, for example). Also, Apple uses the Airport Admin Utility to configure the base station. With other brands it's usually done through a web browser interface.
Chris