As the cliché goes, with great power comes great responsibility. Round 2 of the iPhone revolution brought fans a 3G-capable model with a built-in GPS radio—not to mention plenty of software enhancements that work on both the new model and the original version.Of course, that means there's more to learn. But that's where we come in. We assume you already know how to make calls, surf the Web, synchronize your music and photos, and generally have a good time—but you want to learn some real shortcuts. If that's the case, here's a list of our top tips and tricks for iPhone 2.0, geared toward more advanced users. Want to become a real iPhone power user? Read on.

1. Force-quit an application. Now that the iPhone is a real handheld computer, it's not immune from the occasional misbehaving application. If one freezes up on you, force-quit by pressing and holding the Home button for 6 seconds.

2. Make reservations the easy way. If you're looking up a phone number for something in Safari—say a restaurant or a hotel—there's no need to leave the page when you find it. Simply tap the number right on the page; the iPhone will dial it automatically.

3. Double-down with scrolling. Many Web pages contain separate text boxes with their own scroll bars. If you're trying to move around in one, try this: Zoom in, and then scroll with two fingers instead of one. That will let you scroll just inside the box and not affect the position of the entire page.

4. Maximize battery life, part 1. iPhone and iPhone 3G models have more sensors than just the accelerometer. For example, they have a separate sensor, situated right above the earpiece, that detects ambient light. The iPhone uses this sensor only once per session, though, just as you unlock the handset. But if you cover the sensor as you unlock the phone, you will trick the handset into thinking it's in a dark room, and it will power down the screen brightness as a result.

5. Maximize battery life, part 2. The iPhone's newfound e-mail synchronization abilities are useful, but they also drain the battery more quickly. If that's a concern, under Fetch New Data, set e-mail fetch time to Hourly, and turn Push off.

6. Grab a screenshot. The latest iPhone software lets you easily take screenshots of just about anything. To grab one, hold down the Home button and press the Sleep/Wake button. The iPhone will deposit a photo of the current screen in the iPhone's Photo application.

7. Get a bigger keyboard in Safari. Before you begin browsing, rotate the phone horizontally. Now tap the address bar. Voilà: a wider keyboard. Now if Apple would only add this feature in more applications instead of just Safari….

8. Keep Safari's address bar handy. Ever scroll pretty far down a Web page, only to find that the address bar has disappeared? No need to scroll back up—instead, tap the top part of the screen. The address bar will reappear, regardless of where you are on the actual Web page.

9. Enter punctuation quickly. To enter a period while using the on-screen keyboard, hold down the Punctuation key and slide your finger over to the Period button. Then release it. (This works for all punctuation, of course.)

10. Ride the dot-com wave. When keying in Web addresses, the iPhone gives you a very useful .com button that lets you add the four characters in one press. But as with the desktop version of Safari, you can even leave that out: Safari will automatically add it for you. Bonus tip: hold down the .com button; you'll be presented with a list of alternate domain endings, such as .net, .edu, and .org.