Fusion RIP - ANSI C Source Code
The Fusion RIP source code offering is a high-performance portable software engine that implements IP forwarding and route generation per industry standard RFCs.
Future Software Limited - IP/Routing - RIP
FutureRIP (Routing Information Protocol) software is a portable implementation of the industry-standard RIP routing protocol.
How to Implement RIP Over RRAS in Windows 2000
Microsoft knowledge base article on routing information protocol configuration on Windows 2000 systems.
RIP, Routing Information Protocol
Detailed information on how RIP works
Routing Information Protocol (RIP)
Cisco configuration information on RIP