Have you heard of Boxee?  This is one of the best applications that you can have for your personal media center.  Boxee can be installed on a number of computers such as a Windows PC, Mac, Linux, and even your Apple TV.

Boxee has many features which makes it the best media center currently available:

• Streams videos and music from any available network share to your tv.
• Capable of accessing online music sites such as last.fm
• Able to stream multiple video repositories to your tv such as Hulu and Comedy Central
• Adds a unique social networking element to see what others are watching, and recommend choices to your friends.

For the Apple TV you are going to need a special program, the atvusb-creator.  You can find the program at this website.

Once downloaded, you will use the program to create a bootable USB drive for the AppleTV. Boot from the USB drive, and it will install boxee onto your AppleTV.

All left for you to do is to get an account from boxee, and welcome to the best media center application available.