What sort of arrangement is typical between project originators and the partners they take on for indie games?
Specifically, do these people expect a share of final revenue (if there is any) and for how long is that fair?

It varies depending on what partners you want but i'd be suprised if anyone would consider working for anything less than a share of the project or company that is proportional to the risk they take and the skills they bring (working without guaranteed payment is a risk)

Normally with unpaid indies it doesn't matter who "founded" the team/company, its all about what skills you have and how much work you do. (a partner is not an employee)

1. What sort of arrangement is typical between project originators and the partners they take on
2. and for how long is that fair?

1. I can't imagine anyone giving you money (earning the name "partner") and not expecting a share of any profits. You weren't specific what kind of partners you were asking about. A "partner," by definition, is someone with a stake in the business. Which implies a share of the business's profit (or loss).

2. Usually for the life of the partnership (the life of the business), unless otherwise stated in the partnership agreement. All details of the partnership are negotiable, and must be negotiated at the creation of the partnership.

Recommended reading: http://underdevelopmentlaw.com/collaboration-agreements-and-online-development-teams/

Well the term partner was the closest I could think of but this is still before anything is finalized, which is why I want to know how it should work.
A good rule of thumb here, I think, may just be to put myself in the shoes of the guy I want to work with me.
I'm reading that article now, Tom. Thanks.