I consider myself an expert in attracting free organic traffic, I have been studying different techniques for about 6 months now.
Two of the most effective techniques I have found to work, are creating How To Articles and Videos. Your content should be fresh, unique and helpful. Once you have created some articles and videos just upload them to sites which allow free publishing.
The article submission sites I use are:
www.Squidoo.com
www.HubPages.com
www.EzineArticles.com
and I the video submission sites I use are:
www.Youtube.com
and google videos.
By the way don't just promote your business, you should offer content which can actually help them first position yourself as the expert even if you don't know everything in your subject area.
After you have successfully made some articles and videos start introducing your business. Thats what I recommend.
Your videos don't have to be the most awesome videos you have ever seen, they can just be simple audio with a powerpoint presentation. If you don't have a screen capture recording program I recommend you download the camtasia 30 day trial.
Hope I could help
-- Hamish