The iPhone 4 includes a front facing camera that can be used to photobomb yourself in a stream of action shots. Every photo opportunity is a chance to have fun and fortunately, Apple has facilitated. However, FaceTime is more than just way to take perfectly angled Facebook photos, it's also a way to utilize the iPhone 4's video conference capabilities.
Turn on Wi-Fi to Use FaceTime
In order to use FaceTime, you need to first make sure that your iPhone 4 is connected to a working Wi-Fi connection that has internet access. Launch the Settings app, tap Wi-Fi, and check to see that the Wi-Fi switch is toggled to ON and that you are connected to a chosen network--the one with a checkmark next to it on the left hand side.
If you are still encountering problems, or you are behind a Firewall, check out this handy Apple support document for help.
Check to see that FaceTime is on 
By default, FaceTime is turned off. This is a good thing, especially if your hair is messed up and you're not exactly ready for a video call. But before you can use it, you need to make sure that it's even activated.
Simply launch the Settings app, tap Phone, and then tap the FaceTime switch to ON. If everything worked, you'll see the following message displayed: "Your phone number will be shared with people you call with FaceTime."
If you see a message that reads "Waiting for Activation," wait five minutes, and if it doesn't disappear, restart your iPhone 4 by pressing and holding the Sleep/Wake and Home button at the same time until the Apple logo appears. Then, release both buttons.
Has the status of FaceTime changed in the Settings app after that refresh? If it hasn't, then you might want to give Apple a call at (800) MY-APPLE. If your iPhone is experiencing other problems, like being unable to send/receive text messages or phone calls, give AT&T a shout at (800) 331-0500.
Check to see that Caller ID is on
In this day and age, we all want to keep some information private, including our telephone numbers. Unfortunately, you'll have to engage Caller ID to be able to start up FaceTime. 
Check to see that the setting is on by launching the Settings app, tapping Phone, and then tapping Show My Caller ID to toggle it ON.
Testing FaceTime
Test your setup and get some one-on-one instruction by calling an Apple representative via FaceTime at (888) FACETIME; or, try it with a friend or a loved one to avoid the awkward conversation that could spark from calling a random Apple employee.
