In a blog post talking about the future of Firefox Home (their iPhone app that syncs Firefox history, bookmarks and open tabs from desktop to iPhone), Mozilla dashed any dreams we possessed of a true Firefox browser for iPhone.
While Apple authorized Opera's browser app, Mozilla isn't too keen to try with their browser. They admit that "there are technical and logistical restrictions that make it difficult, if not impossible, to build the full Firefox browser for the iPhone," and instead are much more focused on Firefox Home, which they intend to "bring as much of your Firefox experience as possible to Firefox Home."
Firefox Home is a free app and only requires you to download Firefox Sync, a free add-on to your desktop browser to make it work. Sadly it's the closest we'll probably ever see to a Firefox browser on the iPhone, but Mozilla has got some exciting ideas up its sleeve for Firefox Home. Namely, remembered passwords, integration with iOS 4 features, and other synchronized Firefox customizations. [Mozilla]