There are many ways to develop mobile apps including native, hybrid, and web-based approaches. Native apps are developed using platforms like iOS Xcode, Android Eclipse, and BlackBerry Eclipse but require developing for each platform. Hybrid apps combine web technologies like HTML5, CSS, and JavaScript to create cross-platform apps using tools like PhoneGap, Flash Builder Mobile, and Sencha Touch. Web-based apps are built entirely with web technologies and can be used to augment existing websites.