The "details" of creating a product

I'm curious about getting the ball rolling on a product I've been thinking about for a while. I'd be on the design/develop side of things and would essentially need someone to be interested in doing some of the "architecture" stuff (for lack of a better word). It'd be the server/network/capacity/maybe some database type stuff. The overall product would be a web service, with the possibility of expanding to platform apps (iOS, Android, etc).

Assuming I don't know anyone already that'd be into doing it and that I would trust, what's a good way of establishing ownership, legal protection if the product ends up being good and we actually started something that made money?

Ideally I'd be finding someone about the same experience level as myself. I'm competent with my coding and UI stuff. I work as a developer for my day job. This would be the couple hours after work every night that wouldn't be a paid gig until something "happened". Which it may not ever happen obviously. The way I see it, extremely good experience that has the chance to turn into something.

So anyone with experience here, I'd appreciate some input on things like:

- how to find people that'd be interested in projects like this

- what should be done from a legal standpoint to ensure that everyone is happy and no one gets screwed in case it turns into something awesome

- is this even a realistic way to look at the beginning of a project?

I probably have other questions that I've not thought of yet, but looking to stir the pot as it is.