While both Disney resorts in the U.S offer dining plans, they're very different things. At Disneyland the dining plan is not a good deal. They basically give you $10 vouchers good for dining at any in park restaurants. The problem is that if your meal costs $51 and you give them 6 $10 vouchers, you get no change back, so you've essentially lost $9.
In my experience, it's much easier to get dining reservations at the DLR.