http://www.dotsauce.com/2007/06/06/55-active-rss-directories-to-help-promote-your-feeds/ There you go!
I use these: http://www.pingmyblog.com/ http://autopinger.com/ last I checked I think one of them was not working but I would guess its fixed by now. hope that helps, Nigel
This is a good list as well, and it looks like it was just updated last month... http://www.rssmage.com/
I have a list of over 80 Feed active feed directories in my blog post here if you are still interested. http://marketopinions.blogspot.com/2009/01/list-of-free-feed-directories.html