The only place I know of inside WDW property to get prints made (by "develop" I assume you mean paper prints) is the Kodak ImageWorks in the Imagination pavilion at Epcot. I don't know what the cost is per print, but believe me, it will be far, far cheaper to wait until you get home to get your pics printed.
But let me give yo a little advice - most people who ask this question intend to have their pics printed, then deleted from their memory cards so they can take more pics. THIS IS A HUGE MISTAKE! Never delete your digital files! They are your negatives - keep them forever! On your computer and/or on CD or DVD, those files will last just about forever, while the paper prints can be lost, bend, ripped, burned, stained, or other wise damaged far too easily. And most digital photo prints may say "archival," but in truth they will last maybe 5 years before they start to fade from light or humidity or the acidic paper in some photo albums.
If you only want to print them so you can view them while on vacation, take your camera's cables with you and hook it to your resort TV to look the pics over. But don't delete them! In fact, don't even delete the bad ones to make more room on your memory cards - deleting individual pics increases the liklihood of a card failing, which would cause you to lose lots of pics.
Another piece of advice - don't take a few huge memory cards to WDW. Instead, buy a bunch of smaller cards and change cards every morning. Don't keep more than one day of pics on any single card, and put the full cards in your hotel safe (don't carry them around in your camera bag). This way, yoor pics will be safe even if you lose your camera or bag, or it gets stolen, or if your camera malfunctions and wipes the card in it or it goes for a swim on POTC, the most you can ever lose if one day of pics.