The touch screen interface looks remarkably similar to Apple’s mobile version of Safari with a stop / reload button, and an address / search bar, plus the same star-bookmarking button found in the Firefox 3. As with mobile Safari, the page navigation is at the bottom of the screen with back / forward buttons as well as zoom controls and a tab switch button. For non touch screen devices, a virtual cursor is provided and controlled with the keyboard navigational keys, while other actions are performed through menus and submenus.
As a Firefox user on the desktop I believe the real appeal of Mobile Firefox will lie within the extensions, though so far the mockups don’t reveal any details on this. In any case, the XUL mockups are available for download in both touch-screen and classic versions so you can see how Firefox Mobile is shaping up.