http://www.amazon.com/gp/video/promo/tc/ref=atv_promo_newcust_ce...
This offer is valid only for
first time customers of
Amazon Video On Demand from October 1, 2010 through March 31, 2011.
This credit expires at 11:59:59 p.m. on March 31, 2011.
EDIT: here is how you can view your VOD or MP3 credit, in a clumsy way -
1. Log into your
Amazon account;
2. Go to
http://www.amazon.com/MP3-Music-Download/b/ref=sa_menu_dmusic1?i...
3. On the lower left corner of the page, note "Do you have a gift card?", click on "Redeem it now" (Yes, "Redeem it now" looks very very small)
4. Click on the "Enter Your Code" button, and a small window will pop-up, on the left side, you should see all kinds of credit in your account.