They did say the codes were going in waves. To my knowledge there's been no information about how the waves have been decided or how regularly the waves will go. It also does not at all guarantee that everyone will get their code today - they only said "from...".
Given previous launch issues - and the cross-platform nature of this game - I would expect they're playing it safe and using the waves to 'drip-feed' codes out. They won't want the servers going down on launch day so they'll be adding population slowly, slowly, slowly to make sure the stability is there before adding more players.
Bad news for EU players... that may well mean it'll be late at night by the time our codes come through.
At the end of the day though: we're still getting to play it soon and let's look forward to that.