I'll try and make this as concise as possible. I've been looking for a voip app to use for a while when in no service areas with wifi and internationally. I finally found one sorta. Tikl is a push to talk walkie talkie type of app but the voice quality is amazing only over wifi. Here's the problem. Under menu - settings - about phone - status - phone number....your number is stored. Tikl uses that number to give you your ID so that basically everyone has one and they don't have to make one up for you. My issue while trying to play with it over wifi in airplane mode is that number isn't stored in the phone at all times. I'm guessing it is retrieved from sprint when it accesses the network. If you start your phone up in airplane mode under menu-...-number it says unavailable. Tikl app can't read what your number is so it doesn't allow you to use the app. This isn't the biggest deal in spotty service areas, because most likely your number is already stored, but I wanted something pretty reliable to use over seas and this thing is great. You can even talk on a party line with multiple people at once. Any ideas on a work around. I'm thinking I've got a better chance working with the people that make the app (which I'm doing) but wanted to see if anyone had some thoughts. Also if anyone knows if this is how all sprint phones work or if just the Moment works like this.