Mozilla has launched a contest to spur on development of add-ons for its recently-released Firefox for Mobile browser. Between now and April 12, developers are encouraged to create extensions or other add-ons tailored for the mobile browser. The top ten submissions (as judged by Mozilla's Add-ons and Mobile teams) will each be awarded a package containing a Mozilla t-shirt, phone case, and a brand-new Nokia N900 phone -- which runs the Maemo mobile Linux operating system and was the very first device to support Firefox for Mobile.