I am going to the US for 20 days tomorrow and plan to buy the month's talk and text add-on plan to avoid roaming charges. I am not buying any add-on data. I have my phone linked to my yahoomail account and my facebook account so it chimes every time an email message comes in or a facebook notification. Will this incur data charges while I am in the States? Do I need to disable these features? How can I have the phone turned on for talk and text use, yet not incur charges for data use? What is classified as data use, actually? Is it only viewing the emails, or just having them come in?