*sigh* i feel a dick posting this but... hey ho....
my son is 3 years old, he's been using -his own- ipad since he was 2.
he can now count up to 100 in 6 languages, can do addition subtraction, knows his times tables etc and has just been accepted for Tokyo's only speciailist school for gifted children.
The Ipad is a tool - it's upto parents on how they let their kids use it. Children are sponges and the ipad can be either a distraction or a learning tool.
Please note this is part of ongoing efforts by myself, his mother and his grandfather/mother to ensure he gets as much education as he can. Not everything is evil - everything is a tool that, when used correctly, can greatly benefit children IF used correctly and used in moderation. The ipad HAS inflamed his imagination and his thirst for knowledge. No question.
(to balance this : we've used the wii for the pretty awesome Anpanman game and the odd game of mario kart for him to wind down - but to be honest? games wise he's way more into Trials Evolution
)