Multitasking is a feature of iOS 4 that allows applications to perform specific tasks in the background while you are using other applications. Multitasking in iOS 4 is supported on iPhone 4, iPhone 3GS, and iPod touch (3rd generation).

It is important to create frequent backups of important data. This is even more important if you are using beta software. You should make sure you back up your data prior to entering the MobileMe Calendar Beta.

You can view and share files on your iDisk with the iDisk app for iPhone, iPad, and iPod touch. For help using the iDisk app, open the app, tap Settings in the upper-left corner, then Tap iDisk Help.
If you encounter issues while using the iDisk app, the steps below can help you troubleshoot further. iDisk [...]

By downloading VoiceOver Kit to your computer, your iPod will announce the names of your songs, artists, and playlists. If you no longer wish to use the VoiceOver feature on your iPod and want to remove the VoiceOver Kit from your computer, follow the steps below.

You can purchase the iOS 3.1 Software Update for iPod touch (1st generation) from the iTunes Store using the latest version of iTunes on a Mac or PC. 
Purchase the iOS 3.1 Software Update directly from the iTunes Store.
Own an iPod touch (2nd generation or 3rd generation)? Get the free iOS 4 Software Update for iPod touch.
If [...]

It’s possible to receive a small and quick electrical (static) shock from your earbuds while listening to iPod, iPhone, or a Mac computer.

When you connect an iPhone into an accessory with the “Works with iPhone” label, the message “This accessory is not made to work with iPhone” may appear.

For optimal audio quality, insert the Apple In-Ear Headphones so they have a good seal, and make sure the mesh cap is clear of obstruction. If a good seal is not made, you may notice the audio quality is lacking bass or sounding “tinny.” If the mesh caps are clogged with debris or earwax, you may [...]

Get the answers to frequently asked questions about Bluetooth headsets.

If after troubleshooting your iPhone Bluetooth Headset you determine that a replacement headset will resolve the issue, you’ll need to locate the serial number.