I have downloaded the Google Mail application and set up my two accounts. If I leave the program running in the background am I charged (same applies for google maps as well)..thanks in advance
You'll be charged each time Gmail links to the server to refresh the message list. I don't know the exact interval, but it is several times per hour if you leave the software running in the background. If you exit the software, it is only a few times each hour. You can find the precise intervals by searching either the Gmail site or the Google Mobile site - I don't remember which one I saw it.