I've been thinking about switching over to T-mobile on my iPhone 4 which has been unlocked by AT&T. I'm thinking of signing up for the $30 unlimited text and data plan with 100 voice minutes. This plan can only be signed up for on the web and not in a store so I can't ask my question there. I would ultimately want to port over my existing AT&T number, but would only want to do that after seeing how good the coverage is in my area. Supposedly I'm in a refarmed data area but would want to see how well it actually works before cutting the AT&T service off. So my question is, can I just set up a new number with T-mobile and give it a try for a couple of weeks and then call up their customer service later and ask for my AT&T number to be ported over? Would there be any charge for doing this later rather than at the time of establishing service? Is this likely to be straight forward or will it be a hit or miss nightmare of trying to find a customer service person who knows what they're doing? Really hoping T-mobile can work for me, but would like to give it a test drive first! Used to be a customer until I left just for the iPhone.