If I goto options -> Mobile Network -> set the Data Services to OFF. It will stop the mail synchronization.
How about other applications like CHAT ? Weather updates ?
I want to off all these except phone calls and SMS when I am overseas. Will the above do ? or I need to go to individual applications to switch it off (if any) ?
Exactly what Penguin said. Stops all data. It'll save you loads of $$$ when roaming internationally. It even stops TCP/IP. You'll see the GPRS/EDGE turn to gprs/edge.