My data service has completely stopped working. I am using a factory-unlocked iPhone 4. My iPhone shows 5 bars of signal on the "HOME" netowrk but there is no 3G indicator like usual (no "E" or GPRS indicator either) and nothing that uses data (maps, mail, web, etc) works at all. This just happened today. My iPhone has generally worked OK on Straight Talk since April. 3G speed has been a little slow and inconsistent since I moved to Houston, but generally useable. The data just stopped working altogether today.