We purchased the Leapfrog Word Launch for our smart toddler. Basically the game is very easy- it just plugs into your TV. It consists of an easy touch pad with letter openings and a keyboard with removable letters. It has 4 games on it which are all spelling/word search games. Probably most suitable for ages 3-6.
The features I like most about this product was the low price and ease of playing. My toddler son can easily understand the instructions and play the game independently. And he gets "bonus tokens" for spelling different words, so it has increased his already amazing vocabulary.
I think this would be a great game for children who are in that pre-reading stage. The graphics are fun and not too annoying. The low price was also nice, and lower than many other kids video game systems available.