Toddler through elementary School: Reader Rabbit, JumpStart
Preschool: Clifford the Big Red Dog, Winnie the Pooh, Diego, Dora the Explorer
Elementary School: Magic School Bus, Cyberchase, Bookworm
"Jumpstart" is a series of games for young children. "Dr. Seuss" also has a line of games (largely for reading), as does "Dora the explorer", "Clifford learning activities" and "Arthur". "Dr. Seuss" also has an interesting website with a few online games.
