Okay, it seems they are not giving codes out anymore. see facebook announcement http://www.facebook.com/group.php?gid=320859561633
It sez to go to the spread aeria blog http://spreadaeria.wordpress.com/
They have all the information there about making submissions.
FYI, "submissions" means URLs that point to where you have made comments on online forums about Aeria Games. The rules say it can't be spammy but needs to relate to Aeria and/or an Aeria game and provide links/web address to them.
hope this helps