You need to first access the Bungie website to get your actual keys. At first the site was not responding at all, but just recently it seems to be functioning. It is slower than usual, but at least you can access the keys.
The bad news? Well you then need to take those keys to the PlayStation Store which is still suffering outages at this point. Players are trying to access the store through consoles and computers with hardly any luck. A lucky few are breaking through to at least input the code and download the first file, but upon launching Destiny they get stuck as you then need to download another rather large file.
Players in the EU region were able to pre-load the game earlier this week and are currently able to play the game. The spradic outages only seem to affect NA players that were not able to pre-load the beta at all.
Sony has stated they are “experiencing a high volume of players” and due to that connections to PSN made be intermittent. Bungie’s and Sony’s social pages are flooded with complaints due to lack of connections. Seems Destiny may be a hit after all! Who knew, right? (Yes I’m joking, I too have been trying to download my beta with no luck.)