Computer Networking Over The Internet

I am looking for suggestions about a resource I can use to establish a network connecting computers at geographically dispersed locations. (I have set up both wired and wireless networks at home and at family locations but now need to try to interconnect those home networks without the use of servers). Some initial research leads me to believe that a peer-to-peer network is what I would need to establish so I would appreciate any suggestions for literature that would guide me through the process. Just to complicate things a bit more, the network would contain both PCs and Macs).