Someone said that setting the region to UK when signing up allows the code to work on US accounts as well. I got my code some days ago but my PS3 won't be here until Monday so I haven't tested it that's true.
And yes, it takes a while to get the email, but you'll get it eventually. Mine took three or four days for my first FB account; it's been three days since I tried with my junk accounts and haven't gotten those codes yet.