From SMART (Office of Sex Offender Sentencing, Monitoring, Apprehending, Registering, and Tracking), Office of Justice Programs, Department of Justice.
A Practitioner's Guide to the Adam Walsh Act
Cases Interpreting 18 USC 2250 (September 23, 2008)
Sex Offender Registration Law Update #21, December 02, 2008
And much more through Professor Yung's excellent blog site on Sex Crimes.