You can try DNA Life. It has many Kids' Theme Wall Coverings to choose from, Disney - Mickey Mouse, Pooh, Princesses, Chicken Little, Cars, Tarzan, Toy Story, Lion King, Lilo & Stitch, Nemo to choose from. Hope this helps.
Visit wallvolution's Online Wall Stickers Store. Here you can find wide range of Wall stickers in different categories. In Children Category so many options available like Disney, Mickey Mouse, Thomas The Train etc...