wow, this is nice.

Windows 7 Federated Search.
This Federated Search will change the scope of your search beyond your Computer. You can now search for items in remote repositories from your PC. It is based on OpenSearch and the RSS format. Since it is based on open standards, it becomes very simple to create custom ‘search connectors’ for your own remote repositories. For example, you can search Flickr or Twitter from within explorer.
Here are some search connectors.

I even created one for my own site , you can download it here