Adding a custom checkbox to sign-up form

Hello Zen Gurus!

I would like to slightly customize the new customer account creation form by adding a checkbox so that when a customer creates a new account, we have a box that asks "Are You a Member of the Wine Club?" at the top of the form.

Ideally (the golden chalice) I would like this to tie into the Group Discount module that I set up that allows for a 20% discount on all purchases as a Wine Club Member.

If that tie-in is too complicated, a static box would do nicely that just indicates WC yes/no on the admin notification email when a new customer creates an account. (we are not Walmart so manual would be ok for now....)

Thought I would pose this to the collective...
Cheers,
Larry

"It said to install Windows XP or better...." so I installed Linux