Make sure to enter the eShop to be able to take part in the program.
http://www.nintendoworldreport.com/news/27392
The deadline to apply for the Nintendo 3DS Ambassador Program is fast approaching. If you have not taken your 3DS online and gone into the eShop before 11:59 p.m. Eastern time on August 11, you will not be able to download the 20 free games when they become available.
There will be 10 NES games available on September 1, and 10 Game Boy Advance games available by the end of the year.
Is there any way to confirm eligibility? I've visited the eShop a few times, but it's a little disconcerting to not have any sort of visible record of it.If you go to the news section on the eShop there is an article that starts with "You are a Nintendo 3DS Ambassador!" But other than that and the spot pass notification that tells about the program, I don't think so.
I've downloaded Pokédex 3D, ExciteBike 3D, and Netflix, so I should be good if there is an issue. Unfortunately, I have a bad feeling there will be, which is based on experience with Club Nintendo and how sometimes certain automatic registrations just don't work for whatever reason. Hopefully this will be handled better than Club Nintendo though.