I will be out of the country and want to use my Verizon Droid without roaming charges. I'll be in both GSM and CDMA countries. I have reviewed (and am confused by) fring, Skype Mobile, SIP, etc. I understand that I can use wifi when in airplane mode but Skype Mobile requires a Verizon signal/roaming. I want to call cell phones in the US. What do I do?