Your iPhone can capture full 1080p video, making it a surprisingly robust tool for all kinds of moviemaking: vacations, family events, Bigfoot sightings, or even the indie film you're hoping to debut at Sundance.
Of course, out of the box there's no way to join or split clips, add titles, create a soundtrack, or apply special effects. For most users, the go-to tool for such video-editing tasks is Apple's $4.99 iMovie. Now, there's another option: Pinnacle Studio for iPhone ($9.99).
Update: Pinnacle is currently offering a limited-time introductory price of $4.99.
The same core set appears here. To build a movie, you simply drag a photo, video clip, transition effect, title, or song to the storyboard or timeline, then arrange those elements to your liking.
The app also lets you trim and split clips, overlay sound effects and voice recordings, add custom pan-and-zoom effects, and so on. It supplies various motion and static titles, but you can edit things like colors, fonts, and sizes to create customized text.
For the iPhone edition, Pinnacle had to rejigger the interface for a smaller screen, though not as much as you might think. This remains an admirably simple app to use, especially if you watch the 5-minute tutorial video that shows you around the interface.
When you're done editing, you can export your movie to Facebook, YouTube, or even Pinnacle Studio for PC or iPad. However, the app still supports only one cloud service: Box. Why there's no option for uploading to Dropbox, Google Drive, OneDrive, or the like is beyond me.
Even so, if you want to edit iPhone movies on the go, Pinnacle Studio gives iMovie a run for the money -- even if it costs twice as much.