Hi Julie,
First of all, Happy Birthday to your son! What a great way to celebrate his special day. Be sure to get a birthday pin at guest relations, so that cast members can wish him a Happy Birthday. Also, if you are dining at any table service restaurants that day, let them know that you are celebrating as well.
Are you looking to dine with characters on your son's birthday? If so, Chef Mickey's and Garden Grill are both fun restaurants featuring Mickey and pals. Some other options for a fun dining experience are Whispering Canyon Cafe or 50s Prime Time Cafe.
The Free Admission on Your Birthday promotion ended on December 31, 2009. So unfortunately, your son will not be eligible for the gift card.
The promotion for 2010 is called, Give a Day. Get a Disney Day. By participating in select volunteer opportunities in your neighborhood, you can receive a free, 1 day admission to a Disney park. Click
HERE for more information.
Hope this helps. Have a magical vacation!