SoundStepper is a "100% software" telescope controller, for Windows, using audio hardware to control step motors at real time. All it requires to operate are external step motor drives, which can be a commercial "pulse/direction" drive or analog current amplifiers.
Documentation: http://soundstepper.sourceforge.net/
Squidge is a Linux distribution based on OpenWrt Kamikaze (unstable) branch aimed at electronics enthusiasts. Required hardware is the Edimax BR-6104KP router or a modified Sweex router with added USB.