Originally Posted by SoulSnatcher
The NES games for the Ambassador Program are now available for North American 3DS users. For some users, the games might not be available right this moment but that should be rectified soon.
To obtain the games, log into your eShop account, click on Menu, then Settings / Other, and then select Your Downloads. The NES titles should appear there as software you can "redownload".
You can also obtain an Ambassador Certificate which provides more info about the Ambassador Program and can be used as proof of your entry into the program.
The games that are available for download are,
Super Mario Bros.MetroidThe Legend of ZeldaWrecking CrewNES Open Tournament GolfDonkey Kong Jr.Balloon FightIce ClimberZelda II - The Adventure of LinkYoshi