I can see how your podcast has done wonders for you Timbo. For anyone else our there, I definitely recommend listening to the 'Small Business Big Marketing' podcast at
http://smallbusinessbigmarketing.com/. We've got quite a few of our clients listening to it now after recommending it.
For Engage Marketing, i'd say that Word of Mouth provides most of our work, with search engine leads coming in at a close second.
For The Blog Designer, most of our sales come through a pretty casual affiliates set up. We look after our affiliates and they like us, so we both end up happy. We're just about to launch a few out of the box marketing promotions which I think will end up providing the majority of our business. Stay tuned!