The video embedded below was shot and edited completely on my iPhone 4 using iMovie for iOS:
It's not going to win any academy awards - but it's crazy to think what's possible with a device that slides into your pocket. Shoot HD video, edit it, add titles, and then upload it to the internet or email it to a friend.
While in some ways it's more frustrating trying to do the edit on a small screen as opposed to using a "real" computer - and my experience is on the smaller iPhone display. An iPad would make this much easier to do. On the other hand, in many ways it's much more intuitive. By being able to use my fingers to drag in/out points around and just touch what I want to change, iMovie for iOS gets the interface out of the way and lets me edit the content directly.
With a computer you have to figure out how to use a mouse with 2 or more buttons, and some sort of scrolling mechanism. Plus you still have to figure out the interface of the program you're using. On an iPhone/iPad (or any modern touch device), the mouse is taken out of the equation. You still have to learn the interface for the particular application you're using, but there's no worry about using a mouse and trying to correlate that to onscreen actions.
You can be as jaded about technology and about Apple in particular, but it's pretty impressive how far we've come in the last few years.