Apple’s iMessage is a great free service that allows you to interact with friends, friends, family and co-workers who also have an iOS device or a Mac. You can send text messages, photos and even videos. Not only is iMessage free, but it also helps you bypass costly SMS and MMS messaging charges associated with your carrier. Those of you with a WiFi-only iPad or iPod touch can also enjoy sending messages without a cellphone plan using your Apple ID. Read on for our full guide on how to setup iMessage on iPhone, iPad or iPod touch.