Labradoodles have had a few registries in the past (think AKC breed club but for doodles without the 'show')
Now goldendoodles have a registry too!
The Goldendoodle Association of North America (GANA) has launched and is open for membership. I don't know everything about it, but I appreciate that breeder members will have to abide by a code of ethics and will be required to have certain health clearances on all breeding dogs.
GANA will be open for membership to GD owners in the future, but you'll have to check their website for more info on what that will entail/benefits, etc:
http://www.goldendoodleassociation.com
(The main Labradoodle registry is The Australian Labradoodle Association of America:
http://www.ilainc.com/index.html -- not sure if it is only for Australian LD's or all LD's)