Shooting a band benefit (volunteering services)

[GadgetRick]

So my friend and I are volunteering to shoot a band benefit for Habitat for Humanity in May. They have agreed to let us be the photogs, which is cool. Obviously, I want exposure and will ask for that (announcements about us, maybe a banner, etc.). However, does anyone have a contract they've used for an event like this which I can use to modify? Obviously, we want to ensure we've got access to everything as well as retaining the rights to our images, etc. Just wondering if I should add anything else.

Thanks.