1. Federal Government: Includes all Federal inmates from 1982 to present.
http://www.bop.gov/

2. Arizona: Current and past inmates
http://adcprisoninfo.az.gov/ISearch.htm

3. Arkansas: Incarcerated
http://www.state.ar.us/doc/inmate_info/

4. Florida: Currently incarcerated
http://www.dc.state.fl.us/activeinmates/search.asp

5. Illinois: Incarcerated and supervised release
http://www.ag.state.il.us/communities/somb/registry.html

6. Indiana: Current and past inmates
https://secure.IN.gov/serv/cji_sor

7. Kansas: Discharged and supervised release
http://docnet.dc.state.ks.us/POSTREL.htm

8. Maine: http://www.informe.org/PCR/

9. Michigan: Incarcerated and supervised release
http://www.state.mi.us/mdoc/ASP/otis2.html

10. Minnesota: Incarcerated and supervised release
http://info.doc.state.mn.us/publicviewer/main.asp

11. New York: Current and past inmates
http://www.docs.state.ny.us/

12. North Carolina: Incarcerated, supervised release and discharged
http://webapps.doc.state.nc.us/apps/offender_servlets/menu1

13. Ohio: Incarcerated, supervised release and discharged
http://www.drc.state.oh.us/search2.htm

14. Pennsylvania: Inmates currently under supervision of Department of Corrections
http://www.psp2.state.pa.us/SVP/index.htm

A private organization that offers to search public records on the internet: Public Record Finder - http://www.publicrecordfinder.com/sexoffenders.html