I don't know what is that: amazing Web searching skills or inability to explain the requirements for the search result in a question (note that you did not specify the implementation languages you would like to consider).
Please do it again:
http://bit.ly/19GWVtK[
^].
Note that on the very top of search results you get two the most adequate results, and the first of them is a CodeProject article:
Developing Firewalls for Windows 2000/XP[
^],
http://sourceforge.net/projects/firewallpapi/[
^].
The second one referenced above is the SourceForge project, and SourceForge is a very reputable source of code; and #4 in search result is from another reputable source, CodePlex:
http://netdefender.codeplex.com/[
^].
You need to do something with your skills. I hope just a little practice will quickly fix them. :-)
—SA