Once your logged in and become a fan, go to the "Free Shrimp Taco" tab and be ready to print your coupon. The coupon I got was valid until 3/04/2010. Limit one coupon per person per visit. Not valid with other offers or coupons. At participating locations.
Get more free stuff from Del Taco by joining their Raving Fan eClub. You get two free Chicken Soft Tacos just for signing up, a free Premium Shake on your birthday plus you'll be notified of future special promotions and offers. Visit the Del Taco website for more information and to find a location near you.