The is the fifth installment...go to link to see them all. There will probably be many more:
George W. Bush has attached signing statements to more than 100 bills before signing them, within which he has made over 1,100 challenges to provisions of laws passed by Congress. This figure exceeds the total number of such challenges by all previous presidents combined, and Bush has used this practice to exempt himself, as President of the United States, from enforcing or from being held accountable to provisions of the said laws. By declining to veto bills, and instead attaching signing statements challenging laws passed by Congress, he has violated Article 1, Section 7 and Article II, Section 3 of the U.S. Constitution. These articles of the Constitution dictate that the president has the option of signing or vetoing a bill, and upon signing the bill to "take care that the laws be faithfully executed."
http://english.ohmynews.com/ArticleView/article_view.asp?menu=A11100&no=340571&rel_no=5&back_url=