You paid for a 4-inch screen. Make sure you use all of it. The iPhone 5 features an 1,136-by-640 display, just a bit bigger than the 960-by-640 panel on the iPhone 4 and 4S. To take advantage of the whole screen, developers need to rewrite their apps. Some have jumped to the task. Some are taking a little longer.

This isn't the first time Apple has pulled the different-screen trick on devs, but it's only the second time the company has asked them to change the aspect ratio on their iOS apps. The first time, with the iPad, worked out well; there are now more than 250,000 apps designed for the iPad's screen size. I'm confident that with Apple reporting 5 million orders of the iPhone 5 so far, developers will find a large enough market to offer iPhone 5 versions of their apps promptly.

The iPhone 5's additional screen space doesn't completely transform the iPhone experience, but it's helpful. Typically, you'll see a few more lines of text or a bit more of a game's background. If you really want to show off your iPhone 5, in the App Store, look for games that take advantage of the new A6 processor, like Lili in the games section on the next page.

Almost all iPhone apps will run on the new iPhone 5. They'll just show up 'letterboxed,' with black bars at the top and bottom to simulate an iPhone 4S's screen size. To help you get the most from your iPhone 5, I've found 20 entertaining apps that fill the whole 1,136-pixel-long screen. More full-screen apps are appearing every day, but of the more than 100 apps I tried, these were my favorites that ran in full screen. I've divided them into categories, and you can click on each app's name to download it from the iTunes App Store.