In an earlier blog about Html Entities and Unicode I touched on the HtmlEncode() method.
This page UrlEncode vs. HtmlEncode contains the complete framework HtmlEncode() method using Reflector. It clarifies exactly what to expect from the method, and confirms that HtmlEncode() only converts a subset of Unicode characters into Html Entities (eg. Ӓ).
OT: I really like the look of this site, too.