There are so many useful sites for first graders...
I have joined a few sites that I feel will enhance the concepts I am expected to teach in first grade... The list could go on forever...
ReadingA-Z.com (paid site)
Epic Book (paid site)
Children's Books by age and subject
(if you are looking for books that are "similar" to the ones your child enjoys)
Brainpopjr.com (paid site)