Vanguard - Naming Policy @ Official Site
The official Vanguard: Saga of Heroes site has been updated with a look at SOE's naming policy.
SOE is fairly flexible when it comes to naming. Be aware that while some names do not violate policy, they still might not be the best choices. Pick your name wisely; your reputation may rest partly upon it! While the name N3wbPwn3r clearly shows a player's IQ, some may say it doesn't fit within the world of Telon.
Source: Sony Online Entertainment