If you mean how to take on the role of the promotional end of an endorsed mailing JV, your assumed analogy puts the cart before the horse a bit ... you should already have a list and/or a reasonable amount of traffic ... or a proven way to quickly obtain either/both of the aforementioned (web 2.0, PPC, purchasing advertising, etc.) ... before you register.
Your fellow partners are looking for potential JVs that already have the ability to sell ... so I would tackle that obstacle, first ... before registering as a JV partner.