Pay per click vs SEO

I see that B2B Marketing is holding an event on December 11th entitled 'Is SEO eclipsing pay-per-click for lead generation?'

Yesterday I was at London Metropolitan University giving a workshop on online marketing to a group of women entrepreneurs-to-be, and the subject of SEO and pay per click fascinated them. When searching on Google, the majority claimed never to click on the right hand column, tending instead towards those on the left, even though they weren't all aware of the difference between which were paid for links and which were 'natural' search results.

The idea that your business could appear high up in searches without you having to pay for it was a revelation. If it's free, they wanted to know, why do people bother to pay - especially as more searchers seem to click on the left hand column anyway?

Although there's a stock answer to this, it's still a good question, and clearly one worthy of debate!