How to Set up a Yahoo Mail Account on the iPhone. The "Mail" application on the iPhone is compatible with a variety of email programs, including AOL, Gmail and Yahoo. The iPhone comes with a free Yahoo "push" mail account that will automatically transfer all email to the iPhone after it is set up. If you already have a Yahoo email address that you would like to continue using, there are a few steps you will need to complete to set up access to the account on your iPhone.
Register for a Yahoo "push" mail account on the Yahoo Mobile website (see Resources below). Yahoo will ask you to provide your full name, gender, birthday and postal code and will then allow you to select a username and password as well as a security question to use to retrieve your password if you lose it.
Turn on your iPhone and tap on "Mail" on the home screen. Tap on the icon labeled "Y!Mail" and then type in your name, full email address and password into the required field. The iPhone is specially designed to work with Yahoo mail so this is the only set up required if you have registered for a new Yahoo account.
Tap on "Settings" on the home screen of the iPhone if you need to set up access to an existing Yahoo mail account. Select the "Mail" icon from the menu and tap on "Add Account" and then "Y! Mail." All you will need to do next is enter your name as you would like it to appear on emails you send, your email address and your password.
Connect your iPhone to your computer and launch iTunes. Select the "Info" tab and then click on "Select Sync Address Book" or "Select Sync," depending whether you are on a PC or Mac, to sync your contacts from your computer to your iPhone. Click on "Yahoo Address Book" from the menu and your Yahoo contacts will be transferred to your iPhone.
Transfer your existing email messages from Yahoo to your iPhone by clicking on "Sync Selected Mail Accounts" from the "Mail" settings menu. Your email messages in your inbox and other folders will not be automatically synced with your iPhone when you set up access to your Yahoo mail account. You will need to manually sync them if you wish to transfer old messages, as only new messages will be sent to the iPhone.
Unlike some other email-capable phones, the iPhone allows you to view attachments, including photos, PDFs and other documents. You can also access your Yahoo mail account on the iPod Touch.