Baby Center-  Here is a great website for that has information about baby development and the stages of growth. There is also information about medical and behavioral issues as well, there is even choose a name section for your baby, here the website http://www.babycenter.com/

Williamsville Pediatrics-  Here is another great site for medical information for your child, even if your Ped doctor doesn't practice there
Here is the website, http://www.williamsvillepediatriccenter.com/