For the first time, Microsoft has implemented a “walled garden” (also known as a “curated” approach) for applications on a Windows Phone. Following in Apple's footsteps, Microsoft now prevents the installation of any application that Microsoft itself hasn't inspected, tested, and appraised. Although power users and developers may find this frustrating, in the end, the consumers win because the only applications that make it onto the phone are those that are almost guaranteed not to crash or rapidly wear out the battery.
Every Windows Phone 7 phone comes with an application called Marketplace (see Figure 15-1), which enables users to download, try, and buy new apps. You should familiarize yourself with Marketplace, because understanding the way it works is crucial to your success as an app developer.
If you want to install your own applications on a real phone, which you'll certainly want to do before you submit an application for testing, you need to “unlock” it. You can install any application on an unlocked phone, including the ones that you write and want to test.
To unlock a phone, you need to become a member of the online developer portal, App Hub. Once you're a verified member of this program, you can run the Windows Phone Developer Registration tool to unlock up to three phones per year (or one ...