Before we left for Disney I tried to find info on taking a baby to Disneyland but couldn't find out everything I wanted in one spot so here is my opinion about taking them.
Taking Callia was a great experience. She wasn't just dragged along, she truly enjoyed watching the shows and parades and she was enthralled with the rides she could go on. Callia was 6 1/2 months old but even though she is small for her age she did great on the rides.
Babies can go on all the rides in Fantasyland except for the Matterhorn and maybe Dumbo.
In Tomorrowland they can go on Astro Blaster, Nemo and Honey I Shrunk the Kids.
In Frontierland she could go on the paddle wheel.
In New Orleans they can go on Pirates of the Caribbean, and the Haunted House.
In Critter Country they can go on Winnie the Pooh.
In Toon town there were no rides - Roger Rabbit is (in my opinion)much too rough for babies.
In Adventureland she could go on the jungle cruise, up the tree house and in the Tikki Room.
In California Adventure there wasn't much that she could go on - she could go on the train ride in Bugsland, the 3D show in Bugs Life and the Take out ride in Bugs land. Oh - babies can also go on the carousel, Toy Story Mania (though it would be hard to shoot holding a baby) and Monsters Inc.
Apparently they have baby change areas but I found just as easy to change her in the stroller and to find a bench or the ground to nurse her. She is a quick nurser and I wanted to stay in the area the kids were in so I didn't go looking for the stations.
Remember to take hats, sunscreen, and light blankets to cover them up from the sun. If you go in the fall/winter you will need something warmer for them in the evenings as it can become quite cool. Take a rain cover for your stroller (yeah, ours never left the hotel). Some hotels have cribs you can use. We took down everything she would need food and diaper wise.
So there you have it. My biggest search was for what rides a baby could go on.