Management in a (new) partnership

I'm (stupidly) considering setting up a new business with a friend. It's a web business, based on my idea. I feel he's the right person for the job in all ways (intelligent, honest, technical project management experience), except that he's a close friend. I also know he's interested in the idea. Things I've thought about:

• How well will we work together?
• If the business fails, how will we feel toward each other?
• Will we be able to have non business-related conversations or will we always default to business?

Any experiences and advice would be most appreciated. In particular:

• What's the best way to bring him in? Both in terms of position/role and in terms of our relative 'ownership' of the business?
• How can I best retain general control but maximise his involvement and enthusiasm?
• How can we manage/separate our two relationships (business & personal)?
• How would the business relationship fit in to the Manager Tools paradigm? For example, I recently listened to the peer one-on-ones podcasts.

I look forward to hearing your comments.

Paul