Disneyland (and California Adventures) have tried to incorporate more recent movies into their their parks by either creating new rides or revamping old ones including Toy Story, Finding Nemo, Tarzan, Monsters Inc, It's a Bug's Life, Brother Bear, as well as have character appearances from recent shows. Most notably, DCA is scheduled to open an entire Cars land in 2012. But you should prepare your children if their favorite Disney movie does not have a ride.
To prepare for our trip, we watched a different Disneyland movie each Saturday night for a couple of months. We usually made popcorn and sometimes even had candy (Halloween helped with that). Watching my youngest kids see Dumbo for the first time was amazing. During the lullaby, my three-year-old climbed into my lap and started swaying back and forth. The older kids loved Sword and the Stone (wizards are popular) and Tarzan. Hands down, the family favorite was Peter Pan. My oldest two kids also read a simplified version of Tom Sawyer (they are now eagerly awaiting a trip to the island playground) and Wind in the Willows (Mr. Toad's Wild Ride). They could not believe they got credit at school for reading what they considered Disneyland fun. Depending on the age of your children you will definitely want to see the Toy Story series, Peter Pan, Alice in Wonderland, It's a Bug's Life (there are several rides associated with this one movie), Pinocchio, Dumbo, Snow White, Sleeping Beauty, the Little Mermaid (multiple rides), any Winnie the Pooh, and something Mickey Mouse. Other movies you might want to watch (and this list is not complete) are Sword in the Stone, Star Wars, Finding Nemo, Pirates of the Caribbean, Tom and Huck, Brother Bear, Inspector Gadget, the Muppets, Monsters Inc, and Indiana Jones (we did not watch all the movies on this list).
Certainly Disneyland can be enjoyed without seeing every movie associated with each ride. Splash Mountain continues to be the most (or second most) popular ride in the park and it is virtually impossible to find a copy of Song of the South. Similarly, my children love the Pirates of the Caribbean ride even though they are too young to watch that movie series. Other popular rides are not associated with any movie like Matterhorn, It's A Small World, and Space Mountain. So, do not feel like you must see every movie.
So go ahead and let yourself have some family fun with a movie night and you just might have a better Disneyland experience as well.