[Rails] Extra Fields?

[Russ Smith]

I'm wondering how you would go about putting a "confirm password" field 
into a form and not have it inserted into the database. An example 
would be on the Basecamp sign up form. And also on that page is an 
"accept terms" checkbox. I guess I want to know how do you run these 
fields through validation (model or controller) and not have them 
automatically entered into the database.

Russ