Frank Coding

http://www.codeplex.com/htmlagilitypack

http://htmlxpathtestbed.codeplex.com/

HTML Agility Pack is great for treating html like xml from code.  You can easily load up almost any html document or fragment and modify it to your hearts content.  I have used it in a couple of projects and so far found no major issues, there is even a tester tool now to help build the xpath statements needed to search the document.