PhoneGap allows developers to write mobile apps using standard web technologies like HTML, CSS, and JavaScript. It works by wrapping web apps in a native container, so they can access native device features and be distributed through app stores. Developers can build, test, and debug apps using their existing tools and browsers, then package them into native installers for iOS, Android, and other platforms using PhoneGap or platform-specific build tools. PhoneGap provides a set of device APIs that apps can use to access features like the camera, contacts, and more through plugins.