This is interesting, and a CUFP in my book. I have crossed paths with a convicted felon in my life and hadn't thought about online criminal records. Monitoring his rap sheet to see what he's up to could be an interesting early warning system.
The City Of Chicago
has a interesting system online called Citizen ICAM
that allows you to plot out recent crimes by location on a map. There is a two week delay on the data. Some neighborhoods are more active than others, while other neighborhoods are more active than you'd expect.
I've considered parsing the site to generate email warnings when crimes happen near my home or areas I frequent, but decided it wasn't worth the effort with the two week lagtime. It is still on my list of nifty projects though, because merging the data with a realtime navigation system would be a good way to know you've just taken a wrong turn and parking your car here and walking to the concert is probably not a good idea.