Via this post over on PHP Magazine's site there's some talk about Open Source Business Models - and the original article from O'Reilly's ONLamp.com.

Many of you might have questions around successful business models. Recent Forbes article on SourceForge and the blog on SugarCRM's functionality differences between open source and pro versions raise interesting questions. If you are contemplating on a new open source venture - my recommendation is not to differentiate (functionally) between the commercial and open source versions, like in the case of MySQL's dual license.

He talks about three reasons for adopting open source, typical open source that's leveraged, and a summary of what's the most effective.