My favourite materials for kids are the Super Simple Songs CDs.
Super Simple Songs - Easy English songs for kids.
My students love these songs - and easily learn really useful grammar (and practical English) just by enjoying singing.
I like reading books to them like: The Very Hungry Caterpiller and Where The Wild Things Are.
As for text books, there are a few I like, such as the "Let's Go" series, by Oxford University Press.
Hope this helps