[jseeff]

Incorporation is not a straight-forward question. Depending on what kind of IP you have (if any), what kind of costs and when you anticipate revenues, can all affect your position (notably in respect of future tax issues). Also assuming in all this that we are talking about US jurisdictions of some kind. Generally speaking, you probably want to incorporate before you start incurring significant costs and liabilities or before you start accumulating significant assets (including IP). There are a ton of resources online about this kind of thing so I'd recommend doing a basic google search and going from there but ultimately it is worth speaking to a lawyer or accountant about this.

As for legal docs, this is often a catch 22 for start-ups and again, will depend a lot on your circumstances. What are your risks (i.e. what does your app actually do)? By looking at many different examples online, you can probably get a good idea of the kinds of things you need to cover, but a lot of it will be specific to your business. Many law firms offer start-ups deferred fee structures so even getting a lawyer to help doesn't necessarily have to cost you an arm and a leg....