Google Media Center is a free Windows-only software that lets you stream photos, videos and music from the computer on to your TV.
This requires a Universal Plug and Play compatible device like an Xbox or Playstation gaming console, set-top box or a photo frame like the Kodak EasyShare.
Google Media Server will auto-discover any UPnP device that’s connected to your computer. You can also pick content (like desktop folders, Picasa photo galleries, etc) that should become available to that device.
Here’s a screenshot of Google Media Center admin panel that is available as a Google Desktop gadget. (You therefore need Google Desktop to install Google Media Server.)