Go Mobile is a feature that makes it easy to sign in to Yahoo! Messenger on your mobile phone or other device when you are away from your PC. Your friends will see you as I'm Mobile and will be able to send messages directly to your device. You can now leave your desk for lunch or for the day and keep in touch with your friends and family on your mobile phone.

To register your mobile device:

1. Click the "Messenger" menu in Yahoo! Messenger and select "Sign in to Mobile Device."
2. Select a country and service provider from the pull-down menus and click the "Continue" button.
3. Choose the device type and create a name for your phone. Click the "Next" button.
4. Enter phone number and click the "Next" button.
5. A confirmation code will be sent to your device. Enter the code and click the "Next" button.
6. Your mobile device is now registered.

You can use the "Sign in to Mobile" feature in Yahoo! Messenger, as well as send and receive messages using your mobile device.

1. Click the "Messenger" menu in Yahoo! Messenger and select "Sign into (device's number will appear here)." This will log you out of Yahoo! Messenger on your computer and immediately log you in to Yahoo! Messenger on your device.
2. Click the "OK" button to sign in to your mobile device.

Note: If you do not receive the confirmation code within 10 minutes, repeat the registration process. If you still do not receive the confirmation code, try sending an email message to your mobile device. If you do not receive either message, contact your mobile service provider to find out if your mobile device can receive text messages.

Also note: You need to have a strong signal and be within the coverage area to receive messages. If you are, but are still having problems sending or receiving messages, switch your phone off and back on (as a means of providing an updated "request" to the network).