I have a 4-year-old little girl so I try to stay on top of websites that would interest her. Here are some that I've found:
AGkidzone is awesome! They have videos, games, printables, and activities. We played a game the other day and after each level, you could print off a coloring page. On their site you will find Holly Hobbie, Strawberry Shortcake, and Care Bears.
Noggin also has tons of things for kids to do. There are printables, video, games, activities, and all sorts of things from some of your favorite Nick Jr characters.
Nick Jr has a lot of the same kinds of things that Noggin has. Nick Jr also has some Holly Hobbie activities and recipes.
PBS Kids has music, games, and coloring.
Here are some other sites I've recently found. We'll be trying these out soon.
Let me know what fun activities you have found on the internet.