re: Discovery Rentry - over US
I don’t know of a site that shows the ground tracking of a landing. You can checkout Heavens-Above or NASA’s ISS and Shuttle Orbital Tracking site and click on sighting opportunities to see if the Shuttle will pass over your area. Their Skywatch 2 is the best they offer and you will need Java to run it.
AS I understand the landing is scheduled for the 7th and NASA list Shuttle sightings for my area up to the 8th so you might be in luck for your area.