I am a developer on the mobile Firefox team at Mozilla.
We currently have an iPhone App called Firefox Home, which lets you sync your Firefox tabs, history and bookmarks to your iOS device. You can get it from the app store, or read more here: http://www.mozilla.com/mobile/home/
We have no plans to release the full Firefox browser for Apple iOS devices. The current iOS SDK agreement forbids apps like Firefox that include their own compilers and interpreters:
“3.3.2 An Application may not download or install executable code. Interpreted code may only be used in an Application if all scripts, code and interpreters are packaged in the Application and not downloaded. The only exception to the foregoing is scripts and code downloaded and run by Apple’s built-in WebKit framework.”