Starting a business with a friend

[Limeycat]

A friend and I are planning to go into business together and we want to put together a kind of pre-nuptual agreement that defines the terms of the business relationship, the finances, benefits, commitments, etc.  The nature of the business means there will be few physical assets (initially at least!), the value will be more in the intellectual property of what we each know and what we can do with that knowledge to deliver benefit for our clients.

Has anyone any experience of this kind of agreement?  I'd be grateful for any pointers, suggestions or resources.