I haven't yet tried this app, but Video Zoom Plus ($0.99) would have come in handy a couple days ago when I came across a deer on campus. The deer was fairly close, maybe 20 yards, but it got a bit lost in the video that I took. I wish I had been able to zoom in. And that's what this new app promises -- 5x digital zoom. But if you have a 3GS you'll need to upgrade it to iOS4.