Why send holiday cheer via email when you can do it face to face?  Google recently added voice and video service to its Gmail chat functionality for more personal holiday greetings. The program works completely through the Gmail interface, but you and your Gmail contacts each have to install a browser plug-in to take advantage of the service. Although it lacks some features of stand-alone programs like Skype, the service is easy to use and reliable and serves as a nice alternative to text-chatting with your Gmail buddies.