This video from Analytical Graphics, Inc. shows an updated animated analysis of the break-up of the the 6-ton, bus-sized UARS satellite. It likely will burn up at an altitude between 80-45 kilometers, with an estimated 26 pieces of debris re-entering the atmosphere for land fall or splash down. The debris zone is predicted to be about 500 miles long.
The latest update put out by NASA on the Upper Atmosphere Research Satellite (UARS) is that as of 1:30 p.m. EDT Sept. 21, 2011, (17:30 GMT) the orbit of UARS was 120 mi by 130 mi (190 km by 205 km). Re-entry is expected sometime during the afternoon of Sept. 23, Eastern Daylight Time. NASA says the satellite will not be passing over North America during that time period, but that it is still too early to predict the time and location of re-entry with any more certainty. They will be able to further refine more details in the next 24 to 48 hours.
AGI has created an app for Android phones where you can track the UARS orbit track. See this link for more info.