IMAP e-mail accounts (such as Gmail and Hotmail) keep all of your e-mail on online servers, which means that you can't delete messages or read them unless you are online. Fortunately, you can set up your iPhone/iPod touch to copy your IMAP messages onto the device so that you can work with them offline. Here's how you do it:

A quick and fun way to delete e-mail messages (in the list view of a folder) is to simply swipe your finger across it (in either direction). A red Delete button will appear to the right of the message to confirm the deletion. If you change your mind, you can tap anywhere outside the button to cancel the action. This finger swiping action lets you delete items in a number of the built-in applications.

If you work at a secure facility that prohibits the use of cameras, you can get the camera removed from your iPhone. A service called iResQ (iresq.com) will send you a preaddressed shipping box and will return your iPhone with the camera removed for about $100. This will void your warranty.

If your iPhone locks up or stops working for any reason other than a low battery, you’ll need to reboot it. This is analogous to turning your desktop or laptop computer off and on again, and it clears up a lot of problems. Press and hold down the Sleep/Wake button on the top edge of the device and the Home button until the Apple logo appears on the screen. Then release both buttons and wait until the Home screen appears.

The iPhone is covered by a one-year limited warranty that covers it against defect, but not misuse. So, for example, if you bounce it off the wall or throw it on the ground, you’re responsible for the damages. In addition, if you hack the device, open up the case, or make unauthorized repairs, you void the warranty. You can extend the iPhone limited warranty for an additional year for $69 ($59 for the iPod touch).

Battery replacement kits with instructions and tools are available for both the iPhone and the iPod touch. This approach is usually less expensive than sending the device in to Apple or AT&T, but if you do it yourself, you’ll void your warranty. A Google search will help you find instructions.

According to tests by Apple, an iPhone with a fully charged battery will provide up to 8 hours of talk time, 250 hours of standby time, 6 hours of Internet use, 7 hours of video playback, and 24 hours of audio playback. An iPod touch with a fully charged battery can play music for up to 22 hours and video for 5 hours. There are certain things you can do to improve the battery life: