All 3 of my family's Samsung Focus have the same issue with the AT&T Microcell.  I drop 50% of my battery in 4 hours when I am at home and connected.  At work I can go the entire day with only 20% of battery used.  AT&T needs to fix this!  Without the microcell I only get 1 bar of power in my house and coverage is spotty but when it is off I get at least a full day with battery at about 30% before I plug in at night.