Both of my kids went to Boulevard School in Woodland hills and had good experiences there. (they are in high school now!) It is on Victory Blvd., between Woodlake and Fallbrook. I believe they have Mommy and Me classes, as well as their pre-school classes and they also have Kindergarten. During the summer, they have day camp.
I live right next to Orcutt Horticultural Center in West Hills. It's a great park to wander around in. You enter on Roscoe and it's near Valley Circle Blvd. Lots of woods and trails. Right now it is undergoing many improvements so there are a lot of areas that are off limits. There is also a park in West Hills that my kids call the hill park. It's a steep climb to the top, but once you're up there you can enjoy the view of the valley, picnic tables, swings, slides and sand. The big hill is fun to roll down. One drawback- no bathrooms (last time I was there). I believe the real name is Chase Park. If you take Fallbrook all the way up, make the second right, after you pass Roscoe Blvd., after about 3 blocks you will see it on your left. Knapp Ranch Park in Woodland Hills is also nice. The bottom level has bathrooms, swings, slides, sand, tennis courts and T-Ball/Coach Pitch playing fields. The middle and upper levels have baseball fields for older kids. A lot of the park area is shaded with trees. This park is located just west of Valley Circle Blvd. between Victory and Vanowen, on a street called Kittridge.
Have fun exploring!