Instructions
Setting Up the PlayStation Eye
Connect your PlayStation Eye to a free USB port on your PlayStation 3.
Go to Settings > Accessory Settings and select "Audio Device Settings."
Choose "Input Settings" and select "USB Camera" to set up the PlayStation Eye as a microphone. Once you set it up, you can use the PlayStation Eye in games, as well as to chat with your friends over the PlayStation Network.
Video Chatting with the PlayStation Eye
Sign in to the PlayStation Network, and go to Friends > Start New Chat. Choose "Voice/Video Chat."
Click the "Invite a Friend" icon, which looks like a square smiley face. Choose the friend that you want to chat with from your list of PSN friends.
Enter a message for your chat invitation and send it. The chat will not start until your friend accepts your invitation.