Try ABCpdf from webSupergoo. It's a commercial solution, not open source, but the standard edition can be obtained free of charge and will do what you are asking.
ABCpdf fully supports HTML and CSS, live forms and live links. It also uses Microsoft XML Core Services (MSXML) while rendering, so the results should match exactly what you see in Internet Explorer.
The on-line demo can be used to test HTML to PDF rendering without needing to install any software. See: http://www.abcpdfeditor.com/
The following C# code example shows how to render a single page HTML document.
Doc theDoc = new Doc();
theDoc.AddImageUrl("http://www.example.com/");
theDoc.Save("htmlimport.pdf");
theDoc.Clear();
To render multiple pages you'll need the AddImageToChain function, documented here:
http://www.websupergoo.com/helppdf7net/source/5-abcpdf6/doc/1-methods/addimagetochain.htm