Is there a list of the other 21?
From http://blogcritics.org/archives/2009/02/05/1833542.php
As things stand right now it looks like Oklahoma, Washington, Hawaii, Missouri, Arizona, New Hampshire, Georgia, California, Michigan and Montana will all definitely consider sovereignty bills this year. They may be joined by Arkansas, Colorado, Idaho, Indiana, Alaska, Kansas, Alabama, Nevada, Maine and Pennsylvania where legislators have pledged to introduce similar bills. Twenty states standing up to the federal government and demanding a return to constitutional principles is a great start, but it remains to be seen whether legislatures and governors are brave enough or angry enough to follow through. As the Obama administration and the Democratic Congress push for more expansion of federal power and spending that may help provide the motivation needed for the sovereignty movement to take off.
New Jersey will never follow the trend. Trenton is too busy making up tons of stupid nanny state laws.
Here is a good website to see what states have requested their sovereignty:
http://www.tenthamendmentcenter.com/