PhoneGap allows developing mobile apps using HTML, CSS, and JavaScript that can be deployed across multiple platforms. It works by embedding a webview component within a native container app, and uses a bridge to allow access to native device APIs. Key features include writing code once and deploying to iOS, Android, BlackBerry and other platforms; using standard web technologies; and accessing device capabilities like contacts, camera through JavaScript APIs. Plugins can extend PhoneGap functionality like the Facebook plugin that allows building native Facebook apps.