I just wanted to post a short list of resources that will help you build peer-to-peer applications for Windows 7.
Download the Windows 7 beta here: http://www.microsoft.com/windows/windows-7/beta-download.aspx. If you haven't tried it yet, be quick! Looks like beta slots are running out.
Donwload the SDK for Windows 7 here: http://www.microsoft.com/downloads/details.aspx?FamilyID=a91dc12a-fc94-4027-b67e-46bab7c5226c&DisplayLang=en. The SDK includes everything you need to build applications with the Distributed Routing Table - headers, libraries and even a sample.
Access the DRT MSDN Documentation here: http://msdn.microsoft.com/en-us/library/dd407952(VS.85).aspx. Let us know if you feel concepts are left unexplained or if you have any questions.