One of the things that is frustrating to both clients and REALTORS is that we are prohibited from commenting on whether or not a neighborhood is "safe" due to Fair Housing Laws. (See article "What Realty Agents Won't Tell You.") The web, however, fills that void nicely with a variety of tools, and now there's a new one that looks very useful: CrimeReports.com. Just enter the address and the map populates with recent crime data, including police calls and arrests.
As this CNN article states, the site had its inspiration in a local Arlington County resident, and is not without its own controversy around privacy and other matters. Nonetheless, it's a valuable tool for buyers investigating potential neighborhoods.
It doesn't appear to have Virginia data yet (the site has a form where you can request the data from your local police department); DC and Montgomery County, MD are already online.