Hi littlebelle,
I have very limited experience, but are they an internet-based website? Because if so, they'll need to take pictures (or you provide them with pics), take down your stats/description, services you're willing to do, how much you're to be paid and the areas you're willing to cover/travel to. Not to mention what hours you're able to work.
Hopefully somebody who works with an agency with jump in with more advice.