By linking your Live ID to your user account in Windows 7 (from build 7048), you can now stream your home media to your another PC/laptop connected to a work or public network. Both your home network PC and work network PC should be linked to the same Live ID account. The media is streamed always from home network to work or public network.
This feature partially worked in build 7048, but works pretty neat in the recent 7057 build. Below is a step by step procedure to allow internet access to your home media
Home Network
In your home PC, link your user account to your Live ID
Open Media Player and choose to Allow Internet Access to home media
You can see users who have access to home media in the resulting screen
Now you are ready to stream your home media library
Work or Public Network
In your work PC, link your user account to the same Live ID you linked above in your home PC
Open Media Player and choose to Allow Internet Access to home media
Wait for few seconds, and you will see your home media library listed in the Other Libraries. The remote media library icon indicates that it is being accessed via internet
The file properties indeed show that this is being streamed via internet from your home
If at all your home media library doesnt appear, refresh the Other Libraries list
You can now browse your home media library from your work PC!
One thing to note is that your Live ID account is tighly integrated with your user account in your home network. This enables the media player to remember your home media library. If you ever change your network connection from home to work/public network or vice versa, always remember to unlink and link your Live ID with your user account again. This can change when Windows 7 gets released. For now, enjoy streaming!