Upfront will be small (possibly nil) to prevent time-wasters. We can agree milestones based on nature of project. Once code is flowing onto a shared repository for a couple days, I'll feel comfortable starting the money drip.
C/S corp in Delaware sounds reasonable. A yet to be drafted, founder's agreement to be signed at project start also to protect both parties.
World, great... i have been having this idea running through my head for some time, but need to iron it out a little and do some research .. Am on a 3-6 month project here, will contact you after.