Kideos.com is a kid-friendly video site organized by age groups(0-2, 3-4, 5-6, 7-8, and 9-10) and categories like Baby Einstein, Dr. Seuss, Educational, etc.
Applications for Science Teachers: This site seems appropriate for PreK-4th grade teachers of science. The videos do not have a Science category, however, the Educational Videos section has many science clips such as Sid the Science Kid, How it Works, How it is Made, and How Stuff Works. These clips are great for supplementing classroom instruction and creating engagement.
See a Sid the Science Kid clip below: