A.L.
My husband and I just took our 2 1/2 yr old son to Disney World this past spring. He loved it! We have also gone to Disneyland with him (around 1 1/2) and Disney really makes it easy for you to travel with toddlers.
My biggest tip would be to have a lot of small snacks with you for throughout the day. A small granola bar or bag of crackers sure makes the line go a lot smoother with a toddler! Also, be sure to bring your own stroller. Disney provides them for a fee but we were much more comfortable in our own stroller - and our son even napped in it every day.
Another HUGE tip is that you can get a free cup of water from anywhere you can order food. This is really important as a bottle of water can be $3-4 and you want your son to drink plenty of water while there. If he's like my son and isn't a fan of water, go to the store and buy the small mix in packages of flavoring (near the crystal light, etc) -they even have an apple juice flavored mix in that my son loved.
The gerber infant center is still there, and is awesome especially if you are potty training. The area is tiny and there is really no place to just "hang out" so you only want to go in there to cool off. They do have a nice drinking fountain in there also if you need to refill bottles.
One last tip, go to the dollar store and load up on disney items there and bring them on your trip.
Finally, don't forget to go to California Adventure and go to the playhouse disney show -it's amazing for toddler!
Have a great time.
A.