Click here to confirm if you are an ambassador or not http://www.nintendo.com/consumer/systems/3ds/en_na/3dsambassador.jsp?menu=how&submenu=ctr-ht-amb-lookup 

PD: Dont put in the last number, the one in the square

just checked it...I AM A 3DS AMBASSADOR!!! feel my wrath!!!

A lot of people don't read comments on facebook....also annoying fly on my monitors.

REMEMBER DON'T PUT THE LAST NUMBER (at least in terms of the America).

I'm not an ambassador but those games will still be mine WUAHAHAHAHA!

I already knew i was in, but thanks for giving us a quicker method than logging into the eShop.

wow, i about crapped my pants cause i put in the last number the first time and it didn't work.

I haven't really played my 3ds since i bought in March. I played excitebike for 5 minutes and got bored and haven't turned it on since. These games ought to get me back into it.

I am an Ambassador but the one thing that makes no sense after it confirms you are is this...

"If you have not already done so, connect to the Nintendo eShop today to make sure you are ready to download your free games starting Sept. 1. (How To) Connecting to the Nintendo eShop for the first time after Sept. 1 could delay the availability of the games."

How could you have not connected to the eShop if you are an Ambassador....

2nd method of becoming an ambassador is updating to the latest update before the date that was listed. 

Just to make sure it's clear - I just got off the phone with Nintendo themselves, because I didn't get the link through Facebook and didn't know it was already discussed on there.

Anyways, I had the problem with it telling me I wasn't an ambassador. The Nintendo rep himself - one of their managers, actually - told me that the last number - from inside the box - is unnecessary and is actually specifically causing a problem in the system itself.

I was skeptical to believe it before I got it from him, because without that number, it's not technically MY serial number, y'know? But no, it's good. Do NOT include the last number. Nintendo themselves specifically say it is NOT necessary (even if the site says it IS).

It told me to put the last number and it worked.