Diane:
I use a standard AFM (American Federation of Musicians) contract. You can probably ask
your local musicians union for a copy (even if you're not a member - tell them you want
to book if you can't think of anything else - or let me know and I'll send you one
snail mail). I remember either the FHJ or the AHJ having a two part article on business
practices for harpists and including a sample contract. I can't remember the issues,
but maybe someone else out there can. (I think Penney Beavers wrote the article??)
The most important thing is covering the details. Payment, deposits, payment for
overtime, what happens in case of cancellation (either yours or theirs), etc.
It's usually the little things that goof you up if you're not careful.
Good luck!
Robin