C# Network engine

Since you asked, I don't feel in the slightest guilty for linking to mine, or you can look at other articles in the same section if you don't like mine.

One simple solution is to use the system sockets library, or the tcpclient or udpclient wrapper classes, and then put your own state management on top of that. Just using serialization would be the easiest option, although perhaps not the most efficient.

I've been using the Lidgren network library lately, it's a C# wrapper that has reliable UDP and some other nice features. You can find it here:

http://www.lidgren.net/wiki/doku.php?id=lidgren.library.network