here are a few good starting points for the up-and-coming network programmer.
-rich
TCP/IP FAQ
http://www.cis.ohio-state.edu/hypertext/faq/bngusenet/comp/protocols/tcp-ip/top.html
Winsock and TCP/IP Resources
http://www.webcom.com/~llarrow/winsock.html
DirectPlay Overview
http://www.microsoft.com/directx/overview/dplay/default.asp