You need to understand that realtors and lenders are prohibited from discussing crime, school quality, demographics, religion, etc. because it violates Federal and State Fair Housing laws.
Therefore, you will need to do your own research. As a former realtor I always advised clients to visit or call the local police departments, use the Census Bureau's website - http://www.census.gov, visit the local schools and have the Parent Teacher organization contact you, visit local parks / playgrounds and speak to local residents and be at the local elementary schools during morning or afternoon drop off / pick up when parents are dropping off or picking up their children. Parents LOVE to talk about their school, neighborhood, etc. They will give you the latest information regarding crime and everything else you need to know.
I don't recommend any of the websites that realtors suggest (listed in Sheryl's reply below). These websites get information from either the Census Bureau or other public websites. They are not accurate but just to serve as a guideline. Realtors recommend them because they are so nervous about violating Fair Housing laws and losing their license. So to realtors, this is an easy out.