Worried about losing your iPhone? Should that dire event ever transpire, you can improve your chances of getting the phone back by adding your contact information to its lock screen. That way, whoever finds it (assuming he or she is a Good Samaritan) will instantly know how to return it to you.
To set this up, select an image you want to use as a background for your phone’s lock screen. Crop it to 320 x 480 pixels. (You can do that in Preview by dragging to select a portion of the image until it’s the right dimensions, then choosing Tools > Crop or pressing Command-K).
Open the cropped image in your favourite photo editor and, using its Text tool, overlay the image with some information giving your contact details, such as name and phone number (but make sure you don’t give the number of the iPhone). Save the picture wherever you like on your Mac.
Next, open iPhoto and import the image. (You can do so by dragging the photo from your desktop into the iPhoto window.) Then, open iTunes and plug your iPhone in to your computer. When the iPhone appears in the Source list, select it, and then open the Photos tab. In that tab, make sure the Sync Photos From iPhoto box is checked and that the event or album containing the image you just created is set to be synced. When that’s done, sync your iPhone.
When the sync is complete, open your iPhone’s Settings app and go to Choose Wallpaper. Find and select the image you’ve just created, then press the Home button. From now on, if someone finds your phone and turns it on, they’ll see the lock screen – with your contact information on it.
If you’re using iPhone OS 3, go to Settings > General to set your wallpaper, and then tap the album in which your image resides to add it as your lock screen.