Something that might help you figure out how much data you'll use per month. I checked to see how much I was at before going out this morning. Drove around using a GPS program (Motion-X - very good!) and listening to Pandora. Did this for about 2 hours and used close to 40 meg. I'm going to check it a few more times while I'm out running these programs but it seems like they used about 20 meg per hour. So I'd get about 100 hours from my 3 gig plan (3 hours per day).