I have an LG 500 :)
On my old non Android handset I had Internet and MMS APNs configured and never got data charges
My wife and I noticed small data charges for our new handsets.
She wants the ability to pxt and I found that to pxt requires the Internet APN and Data enabled over mobile networks
I removed any Internet widgets etc from the home screen [weather etc]
I have turned off background data under Accounts & Sync
I have not used the browser or maps and I still get a 0.17c charge per day
Any ideas ?