Those that logged on to eShop before 11 August will get the message on 10 August as shown in the photo... so if you did not get that message then I'm afraid probably you are not part of the Ambassador program...
I have just logged again and got Ambassador update, the photo below is mine

Aug 14 2011, 12:43 AM
Quote
0.0377sec
0.41
7 queries
GZIP Disabled