How do I do facetime from my iPhone 4 to an Ipod Touch 4th Gen?

When calling an iPhone 4: Use the phone number of the person you are calling. When calling an iPod touch (4th generation): Use the email address designated <a href="http://www.howtofacetime.net/about-facetime.html/">About Facetime</a> of the person you are calling. If you add the e-mail that is linked to the persons facetime to your contacts, there will be an option to facetime them under their contact info.