iMovie
Apple released an app version of its popular iMovie software in June right after the iPhone 4 launch, making it the first smartphone app that lets users edit video on the go. The iMovie app complements iPhone 4's abilities to shoot video directly onto a smartphone and allows users to shoot, edit and share video files using finger taps. You can work on multiple video projects, import photos and additional audio tracks to use with the video as well as pick from several themed transitions and titles to put on top of the footage. Once you're done editing you can export the video (in either a medium, large or HD version) and upload it to the web, send it to friends via e-mail or sync back to your computer. It may not be as sophisticated as a video editing program on your desktop, but for a smartphone, it works just fine.
Price: $4.99 via iTunes