As part of the work that we are doing to implement Windows.Forms in Mono we needed to provide a WebControl that applications could use to embed a Web browser.
We needed a bit more control than the control that gtkmozembed offers. Zac Bowling started the work to wrap Mozilla and Andreia Gaita completed it:
See Andreia's post on wrapping Mozilla for use in Windows.Forms.
The public interface is Mono.WebBrowser which currently only provides access to Mono.Mozilla, but we envision that we will have other providers as time goes by (in particular our users on MacOS X with Windows.Forms).