Yes, all the bathrooms have changing stations in them. I read another thread a while back where someone stated that even the mens rooms are equipped, so dads, you have no excuse not to change a diaper! LOL The changing areas are nice and big and usually are stainless steel or that corian-type counter tops. The baby stations have nice padded ones though and are kept much cleaner, however I only had the opportunity to use it 1x in my last 10-day stay. I bought a few travel packs of anti-bacterial wipes and wiped down the counters before each use. It only took half a minute and made me feel better about using it. Those things came in so handy during out trip!
Here is the info regarding where the Baby stations are. I got this off of
Debs site (This site has tons of info, I highly recommend you take a look) :
Where are these Baby Stations?
Magic Kingdom -- at the end of Main Street, behind the Crystal Palace Restaurant on you way to Adventureland. It is tucked away in a small courtyard near the first aid station.
Epcot -- on the backside of the Odyssey Restaurant on the walkway from Test Track to Mexico. This is a very neat station as many times the workers from the Mexican Pavilion come over to relieve the cast members. It is great to talk to them about their travels and country while you are taking a break.
MGM-Studios -- just inside the entrance near guest services on the left as you enter.
Animal Kingdom -- near the Creature Comforts gift shop in the Safari Village on the left side of The Tree of Life.
HTH!
Most, however, do have one in the ladies and the men's room. We found that there was often a line at the changing stations in the ladies room (typical for a ladies room) and we could get done quicker if daddy would do it. 
