Hi all,
I've recently used a cross-platform browser plugin library, that turned out to be really awesome. Worked immediately, with OpenGL context, supporting Active-X and Netscape-based browsers on Windows (basically all major browsers), browsers on MacOSX and Linux. It saved a lot of time and energy. Has support for receiving calls / sending calls to JS in parent HTML page as well. Really nice piece of work, and it's freeware.
Library is: FireBreath
Can be found at: www.firebreath.org
LiveChat with dev team is very helpful, especially for newcomers.