SteamKit2 is a .NET library designed to interoperate with Valve's Steam network. It aims to provide a simple, yet extensible, interface to perform various actions on the network.
For information on how to get SteamKit2 and add it to your project, please check the Installation Guide.
Check the Getting Started page for a crash-course in using SteamKit2 in your project.
If you're adventurous and you'd rather learn by example, check out the sample projects.
.NET not your thing? Check the Ports page for a list of libraries similar in nature to SteamKit2, but written in other languages.
If you are interested in contributing to the SteamKit2 project, check the Contributing page.
For a list of people who have helped by contributing to the project in the past and present, see the contributors page.
The best place to stop by for support would be our IRC channel.
Here you'll be able to ask Steam and SteamKit2 related questions to an audience of people that may be familiar with the topic at hand.
See the IRC Etiquette page for some tips on how to ask questions in our channel.
If you don't have an IRC client, try GameSurge webchat.