As a proud and obsessed overplanner, here is what I would do.
1) Countdown Calendar.
I bought a big one @ $1 store, loaded it up with Disney stamps/stickers
and made mickey head stickers (xyron). We leave 5/28, had it up for
3 weeks+ now. Gives you something to look forward to every morning
2) Join Tourguidemike.com
3) After joining TGM, print out all the info. you will need. Park schedules,
events, busiest days, etc. Then make a list of what parks you are going
to do & what days. Put them into the schedule avail. on TGM. This coul
take awhile (which is good
)
4) Create a "Disney Master Plan". I buy a soft side vinyl 3 ring binder (1/2")
and a plastic folder/pocket insert. I put everything in this thing. I make
the park plans, make a really nice ADR list (complete with pictures)
laminate index cards, coupons, you name it. EVERYTHING goes into this
folder. It's really nice because as info. is updated on TGM, I can just pull
& replace.
5) Make packing list. There is a good one on allearsnet.com. I made my own
alphabetically (I know, I'm a dork)
6) Figure out how many clothing items will be needed for trip (socks, under
garments, etc) and get any shopping you may need done. Get big
ziplock bags for each day per child, easier to pack and you don't forget
anything.
7) Print all airline, rental car, hotel info. and put in folder.
8) Make checklist of everything you will need and keep adding.
That's all I can type right now, if I remember any others, I'll add to. Hope it gets you started
Its fun finding new places to hide them.. In his lunch, on his rearview mirror, in the shower, in his reading book, my favorite though was on the inside lid of the toilet.....( hey, he almost pee'd on mickey!! 
)
LOVE 
