On Reddit, user AgriosEndendros took a picture of the Sony store on his PS3 showing pre-loading will be available on Sept 4th. While this isn't completely surprising, there has been a distinct lack of pre-loading on either next-gen systems. Hopefully it's not just PS3 that let's us pre-load.

Also, 5 days is really early to be able to pre-load!

Reddit link: http://www.reddit.com/r/DestinyTheGame/comments/262bwv/destiny_available_for_preload_on_9414_through_psn/

No link as it's only in the store on the actual console. And confirmed pre-loading will be available for PS4. It's ridiculous that I was uncertain it would be, but Microsoft and Sony haven't had a great track record with it so far for next-gen.