Well I just tried it and it my cart is 49.99 and it won't take it.
"The coupon entered will not provide a discount based on the current contents of your shopping cart. You may continue checkout without a discount or read the coupon description below and make the appropriate changes to your shopping cart or shipping method selected. Coupon description :
Coupon:FREESHIP2DAY - Free 2-Day Shipping on all orders $39.99 or more. Select USA 2-day as shipping method at checkout. Offer Expires 12/19/08, 10:00 AM."