A single license is intended to be valid for one person only, similar to apps in the Android Market.
The payments are handled through Paypal Express Checkout, and the purchase will be tied to your email address that is associated with your Paypal account.
When the payment has been processed, you will receive an email with a unique code. It is important that you do not share this code with anyone. When you start Roam Control, you will be prompted to type in your email address and your unique code. After retrieving your license from the online licensing server, Roam Control will cache your license and you will not have to re-enter the information unless you uninstall the app or flash a new ROM on your phone.