The Camera app in iOS 4 adds a 5X-digital-zoom slider above the shutter button. The slider is easy to access, but the pictures can get a bit blurry if you zoom in a lot (optical zoom is not available on the iPhone).
When you first open the Camera app in iOS 4, it asks you for permission to acquire [[xref:http://www.pcworld.com/article/192803/geolocation_101_how_it_works_the_apps_and_your_privacy.html|geolocation]] data. You'll see this data in action in the Photos app, in a new feature called Places; your photos appear on a map based on where you took them.
The upgrades aren't limited to your still photos, either. When taking videos, you can now tap to focus on your subject--just as you do when taking photos.