Qik's VideoCamera app isn't the first to give older iPhones video recording capabilities, but it could be the first to do it well enough for non-gimmick use. It'll record at 15fps with various real-time effects, including a Na'vi-inspired blue tint.
Other features include landscape mode, zoom, brightness and audio controls, and effects like black and white, red (?), Na'vi blue, and mirror. It's available now for a buck (link opens iTunes). [Qik]