Skype is a video & audio calling solution from your computer.
There are versions for Apple and Windows.
With Skype you can create an account and call other computer users who have a Skype account.
Paying for a Skype account allows you to call landlines and mobiles.
The use of a usb headphone microphone will improve the quality of the call.
My favorite is the Plantronics , and by using the USB mic you will notice a difference in quality.
For video try any of the Logitech video cameras.
Skype can also be connected to your Facebook account
Remember though , a good broadband connection works best and the quicker your connection and the person you are calling ,the better.