Seriously, we were gonna do this too, then my mate's dad who is a
travel agent and who we booked with (through Virgin Holidays) sorted everyone out when we told everyone to go to him.
Who have you booked with? Maybe worth getting your guests to speak to the same person you booked with if it was in a travel agents?
Also, as some if not most of your guests will more than likely not be as much of a Disney addict/knowledge knower as you, then i recommend you tell them to at least read through Simon Veness' Brits Guide to Orlando - a few of our wedding party have got this on my recommendation (you owe me commission Simon

).
Get your guests to price up dummy bookings with maybe Virgin Holiday's website (again, with many not being Disney fans, a package holiday may be easier than a DIY and make them feel more comfortable) and price up various options.
Find out who is and who isn't hiring a car - this can be important when recommending hotels to them.
For theme park tickets, bare in mind that some of your guests may not want to do the same parks at the same time as you, with the same frequency, for example my mum, dad and nan only want to do Magic Kingdom (well, my dad doesn't, but i DO call him "Mr Happy"

), Epcot and Animal Kingdom as well as Sea World and maybe Universal Studios (not IoA) so i've said they should just buy their tickets out there rather than buy one of the UK options.
If i can think of any more then i'll let you know.
Are you planning on having a party when you get home too? We are and at the moment wish we weren't as it's proving a million times more hassle than the actual wedding!!
Let me know if there's anything you wish to know