A surprising Google Desktop gadget released by Google enables you to share your media across devices. "Google Media Server uses an open technology known as Universal Plug n' Play to stream media to consumer electronic devices. The UPnP specification allows for a variety of hardware (gaming consoles, set-top boxes, photo frames) to communicate and access media from your home PC."
The Windows-only gadget lets you share all the media content indexed by Google Desktop or just the files from some of your folders. Google Media Server can also share some of your Picasa albums (from your computer or from Picasa Web Albums) and the videos uploaded to YouTube.
Google's application requires to authorize the devices that are allowed to access your files, but there's an option to allow any device to access the Media Server.
Google Desktop's blog mentions PlayStation 3 as an example of UPnP-enabled device. Google Media Server's team says that "the only way to connect the XBox 360 to a UPnP server, was to have a service that is only found on Microsoft services (used for registering for DRM content) and for the server itself to be claimed to be made by Microsoft. Legal would not allow us to pretend to be Microsoft (although there are other servers out there that do)."
This is a very interesting way to use Google Desktop: streaming media files that are stored online and on your computer. A recent YouTube blog post mentioned a list of devices that enable you to access YouTube from your living room and Google Media Server is another step in this direction.
If you manage to connect the application to one of your devices, post your feedback in the comments and use the Media Server Group to ask for help.