The folks of over at iPhone Atlas have posted a short FAQ to help guide those interested in upgrading from a 4GB or 8GB iPhone to the new 16GB announced today. In short, you can return an iPhone you've bought within the last 14 days for a full refund to purchase a 16GB model. It'll cost you $10 if they packaging been opened, however. You do not need to sign up for a new contract when switching iPhones. Simply pop out your SIM card from your old model, put it the new one, and activate it through iTunes to use with your current service agreement. Don't have the SIM? Simply activate the 16GB for use with your current your account with a new SIM card. In addition to the U.S., the new 16GB iPhone can be had in the UK for £329 and Germany for 499 Euros .

For the full FAQ, see here.