Before you set up an email account on your iPod 4, you need to make sure you all ready have an email account. There are a variety of free email accounts you can get at places such as gmail.com, mail.yahoo.com, aol.com or hotmail.com, with gmail.com being about the most popular due to the variety of Google services, such as YouTube that automatically tie into gmail accounts.
When you have your own email address, then you can set that account up on your iPod 4. To do this, tap Mail on the Home screen of your iPod and select your email provider. For example, if your email is a gmail account, then your email provider would be gmail. If you don’t see your provider, tap on Other and then Add Mail Account. Follow the steps to set up your account and then you can modify your email settings for your iPod. Tap on Settings, Mail Contact, Calendars, Add Account and follow the instructions in order to modify your email account after you have it set up.
Source Apple Support