Yes. They will send you a temporary card that you can print off, along with a coupon code. When I signed up, I was able to use a free shipping code, the sign up code, and another code all together.
Also, I just got a 30% off coupon in the mail for card holders only. I believe it is October 1-4. Not sure if it is a one time use thing or not but you may be able to find one of those if you sign up for the card.
Re: Gap credit card question..sorry