His group has simultaneously been developing a version of Fennec for Windows Mobile phones. While Sullivan said they've been working hard on it, he wouldn't reveal a release time frame for that browser. His group has also been looking at developing the browser for LiMo phones that are based on the mobile Linux operating system and for Symbian phones, he said.

Mozilla released a in June that offered a first look at Fennec. One unique feature to the browser is that it displays control buttons, such as back and forward, off screen. Users flick the screen to the left or right to display and click the buttons. "One of our big goals is to take advantage of the whole screen, because they are pretty small," Sullivan said. The design lets a Web page fill the whole screen.

He also thinks that Fennec will be unique because Firefox developers will be able to build add-ons for it. "We don't claim to have all the answers. We want to build a great product but make it extensible so anyone can hack on it," he said.

Mobile browsing has historically been a painful experience and countless handset and software makers have created mobile browsers hoping to make them easier to use. While mobile browser development from the likes of Apple, Google and Microsoft is unlikely to cease because of Fennec, other mobile browser efforts may, Sullivan said. "When our browser is ready, a lot of folks will stop building custom browsers," he said. "Carriers and OEMs are telling me they'd rather ship Firefox rather than hack together their own browser."

While he wouldn't reveal names, Sullivan said that Mozilla is talking to handset makers and operators about preloading Fennec onto phones. Traditionally, only a very small percentage of phone users load applications onto their phones so preloading the browser could significantly help distribution.