I got this info today on deferral policy: Note the deferral deadline is the 15th
and the races noted are links to Active.com - that's how you can get to the 2013 races

They also included a pdf of the deferral form I have to complete and return by the 15th.
Dear runDisney Guest,
You are receiving this email because you have requested a deferral from the 2012 Walt Disney World® Marathon Weekend. You are eligible to register for another runDisney race up to one year after your deferral request. You will be required to pay registration fees for the event you are deferring to. Once your deferral form is accepted you will be refunded for your previous registration less the $35.00 deferral fee. Please note all paper work must be submitted 45 days prior to the 2012 Walt Disney World® Marathon Weekend.
Please follow the instructions below to begin the deferral process:
1. Register for the runDisney race you want to defer to
2012 Disneys Princess Half Marathon
2012 Disneys Princess Half Marathon 2 Person Team
2012
Disneyland® Half Marathon
2012 Disneys Wine & Dine Half Marathon
2013 Walt Disney World ®Half Marathon
2013 Walt Disney World® Marathon
2013 Goofys Race & Half Challenge
· If you request a deferral to a race with registration fees less than your original registration fees, the difference will not be refunded.
· If you defer to a race with higher race registration fees you are responsible for paying the full higher fee for registration in the race you are deferring to, along with any processing fees. Registration fees are not refundable.
2. Submit the runDisney Deferral Request Form
· You must have registered for the race you are deferring to AND completed and submitted the Deferral Request Form 45 days prior to the 2012 Walt Disney World® Marathon Weekend.
· Deferral Request Form should be received no later than 2 weeks from the date of registration for deferral to be valid
3. Refund & Confirmation
· Once your Deferral Request Form is received and accepted you will be issued a refund for the registration fees for the race you deferred from (less the $35.00 deferral fee).
· runDisney will send a confirmation email indicating that the deferral form was accepted
Disclaimer
· You may only defer to a race with open registration capacity. All races are subject to capacity and may close at any time.
· Deferral Policy applies only to marathon and half marathon race distances. Deferrals will not be granted for 5K and Kids races distances.
· Race Registrations may not be transferred to another runner.
This is part of what you see when you hit the link to defer to the 2013 Half:
Deferral Registration:
This is a deferred registration link for the 2013 Walt Disney World® Half Marathon. This event is not currently open for public registration. You are being allowed to pre-register for the 2013 Walt Disney World® Half Marathon as a deferral from another runDisney race. Once you complete this registration form and pay the appropriate fees, you will be guaranteed a spot in the 2013 Walt Disney World® Half Marathon.
Hope this helps some of you.