Disneycruise.disney.go.com ... You can link your reservation there. When you'll get to your check-in date, more options will be added to your "My Reservation", you will then be able to book adults only restaurants and excursions. It will remind you a bit of My Disney Experience.
For now, they are using Key To The World cards. You can bring a lanyard on your vacation, it will be useful.
You can add money in your account or drinks and gifts for your cruise. There will be forms you can fax prior to your cruise to order them.