ASP.net Message Board
If you're using ASP.net for your weblog, I have message board classes that can integrate very well into your site. You can see how it works by visiting my weblog. I've got it integrated into my front page, into each article, and into the archive list. The complete source code is available, as is a live version of the sample. It can be used for either restricting comments to your specific weblog entries (as I've done), or as a generalized discussion area (as is shown in the example, which is modeled after this place, of course).
Fog Creek Home