Walt Disney Studios Home Entertainment has launched the "Upgrade2Blu" program, which offers $8 off the Blu-ray editions of the Disney movies you already own on DVD. Just access the
Upgrade2Blu page, select the eligible titles that you own, print out a rebate form and affix proof-of-purchase tabs from the DVDs, mail in the form with the tabs, and you will receive the savings coupon via email.
Disney clarifies that you can keep your DVD copy "to use in your home, car or portable DVD player". So, unlike Warner's DVD2Blu program, you don't have to mail in the actual DVD.
At the time of writing there are 57 eligible titles on the Upgrade2Blu site.
Thanks to forum member "Tonedeaf".