I Phone-4

Per Rick's website, "No Wi-Fi or cellphone connection is required to listen. (You will need a connection if you choose to add audio tracks later.)" So, unless you want to download additional tracks, you will be able to use this app without an internet connection, and should not incur any extra charges. If you do not want to incur roaming charges while in Europe, do the following when you board your transatlantic flight: Put your iPhone into Airplane Mode (this will disable all calls, data transfers, etc.). This will turn off WiFi, but you can turn on WiFi manually if you want -- just make sure Airplane Mode is still on. Also, go to Settings > General > Network, and make sure that "Cellular Data" and "Data Roaming" are turned off. Keep these settings until you return to the U.S.

Rather than use the app, which streams content to your phone, why not download his podcasts from the iTunes Store? They can be easily copied to your iPhone from iTunes.