Remote Potato is a free program that runs on a Windows computer (supports: XP, Vista and Windows 7) that gives you access to your media (e.g. music, pictures, video, etc.) over the Internet. The program also has remote support for Windows Media Center.
All you need for remote access of your content is an Internet connection and a web browser. There is even a mobile application for viewing your content with the iPhone.
(Check out the following web site for more information)