From windowslive
Today, Microsoft Canada announced that Windows Live Photo Gallery 2011 will now support RAW format images. So, you can now view RAW files right in Windows Photo Gallery and Windows Explorer.
The Microsoft Camera Codec Pack is for Windows 7 and Vista and allow you to view and edit RAW files, JPEG, PNG, TIFF for more than 120 DSLR cameras.
Read more about this at: Windows Live blog.
Download the Microsoft Camera Codec Pack at: http://www.microsoft.com/download/en/default.aspx.