bbPress
http://www.bbpress.org
one slight mod to its config.php file and it will share the users db with WP.
yeah but i never get it to work, is it supposed to be missing a stylesheet?
I got my punbb forums put into wordpress pretty well:
http://autohacks.net/news/
Dave
bbpress comes bare naked right out of the box. You need to spin your own css and templates. It is pretty simple, to do, create a folder called my-template (at the root of your install) and start building your template files there, reference bb-templates to see what you will need to build. You should be able to accomplish quite a bit with only creating a header.php and a css.
Some day in the distant future I plan to release a tableless template for bbpress, but I am still working on one or two minor text wrappign issues.
