Articles like the Boston Globe's Bush Challenges Hundreds of Laws mark increased interest in and controversy over the presidential practice of appending interpretive statements to laws.
And now, over at coherentbabble, Joyce Green is building a complete, annotated compendium of President George W. Bush's signing statements. The compendium includes a thorough FAQ about signing statements that explains what they are and why they are controversial, and offers further research advice for anyone who just can't get enough.
[Update: 6.28.2006] For more on the debate about signing statements, visit our colleagues at Vox Bibliothecae and read their post Presidential Signing Statements. And its not just we librarians who care. Now the Senate Judiciary Committee has taken notice and has held a hearing on presidential signing statements.
[Update 7.24.2006] The controversy continues with this report of the ABA's Task Force on Presidential Signing Statements and the Separation of Powers Doctrine (PDF; 34 pages). The Task Force web page reports that "The Task Force will present a report with recommendations to the ABA House of Delegates at the 2006 Annual Meeting in Honolulu, Hawaii (August 7-8, 2006)."