You can use your existing yahoo account.
check out:
http://www.apple.com/support/iphone/mailhelper/ 1. From the Home screen, tap Settings
2. Tap Mail
3. Tap Add Account...
4. Tap Y! Mail
Set Up Your Email Account
1. Enter the settings on the right into your iPhone.
2. Tap Save.
3. The Mail accounts screen will display with your new account listed.
4. Go to the Home screen.
5. Tap Mail and test your new account by sending an email to yourself.
