Jay Sullivan is the Mozilla VP of Mobile at Mozilla. He works on Fennec, the browser for mobile phones. Jay was recently interviewed by Lifehacker. Here is an interesting excerpt:

What we're seeing happen in mobile is just what we've been seeing on the desktop for the last five years. That's migrating from more client-heavy applications to more web-based applications. Fennec is built on the latest version of our browser engine, and has support for offline storage and things called web workers, which enables threaded applications that can run faster. All these technologies make it possible to build a first-class, HTML5-based application. Plus, we're looking at integrating with the devices' capability. A great example of that is geolocation. With a couple lines of JavaScript code, a webapp developer can take location into account. You see that in Firefox 3.5, with Google Maps supporting it. With Fennec, we're giving you that same ability, but I think it's more important in a mobile device. We're also integrating access to [the] device's camera, and we're working on other APIs to let developers access things like an accelerometer.