We went with our 5 and 2 year olds and everyone had a great time. And, yes, don't fall into the "it isn't Disney" trap. It isn't Disney. Disney is unique. Universal is unique. That's not a bad thing.
At US: Jimmy Neutron, Shrek 4-D, Animal Actors show, Woody Woodypecker rollercoaster, ET, Barney show and playground, Curious George playground (has wet areas), Fievel's playground, Men In Black (has height restrictions)... I know I'm probably missing something...
At IOA: Me Ship, The Olive playground (has wet areas), Spiderman (has height restrictions), Camp Jurassic playground, Pteranodon Flyers (you only get to ride if you have a child with you), Jurassic Park Discovery Center, Flying Unicorn rollercoaster, Cat In The Hat, One Fish Two Fish Red Fish Blue Fish, Caro-Seuss-el, High in the Sky Trolley, If I Ran The Zoo playground (has wet areas)... again, probably missing something...
My kids enjoyed eating at Circus McGurkus. We read a lot of Dr Seuss books, so they loved that whole section of the park.
There is some information on the Universal website:
http://www.universalorlando.com/prs_fun_w_kids.html
I know that's not real specific, but I hope it helps!