The orbiter Discovery will return back to terra firma (well, squishy Florida is more like it) on Thursday at 19:05 Eastern time (23:05 GMT), or one orbit later at 20:42 EDT (00:42 Friday morning GMT) if they need to delay. Discovery has been docked with the International Space Station for nearly the past two weeks, where the astronauts on board delivered 9 tons of equipment and one ISS crew member.
Discovery undocked on Tuesday, and NASA has obliged with this seriously cool video (watch especially about 3:30 minutes in when the orbiter is seen from the ISS camera. Wow):
If I can, I'll be live-tweeting the progress of the orbiter on my BANews feed on Twitter.