I\'d love to know if there is such a thing as a Gecko.NET ;) I mean, just like we can embed a WebView and that is an \"instance\" of IE7 inside any Windows Forms application
As of October 30, 2011, there is new information to add since the time of the previous posts. Specifically, while Skybound stopped maintaining their version, there is at least one actively maintained, free, open-source fork available.
I'm using Hindle's fork at BitBucket, which, by virtue of his tool which parses XpCom idls and creates c# wrappers, is rapidly updated with support for each new version of Firefox/Gecko.
See this post for an overview of other choices.