Found this so far:
http://www.Doenetwork.org/
http://www.co.arlington.va.us/police/careers/volunteer.asp
http://www.crimestoppers-ps.com/howtovol.htm
This one being the most promising (if you live in OP).
http://www.opkansas.org/_Res/Things_to_Do/Volunteer/investigations_volunteers.cfm
I will add more information and organize it better as I receive it.