I stumbled on a little blurb about it in one of the newsletters I get. It's not officially being launched until February 14, apparently, but for a while I was able to wander around the website and see what was offered. Now I only get the front page. Maybe you'll have more luck than me!
It seems people will be able to purchase credits toward many different experiences, whether it be for the hotel, dinners, or special events. The credits equal a certain amount of money, which differs from item to item.
Since I'm new, I can't post links, but I guess I can still say it this way:
disneyhoneymoonregistry dot com
Good luck!