Here are some books and articles that have arrived recently:
John R. Koza et al., Every Vote Equal: A State-Based Plan for Electing the President by National Popular Vote (2006)
National Research Council of the National Academies, Asking the Right Questions About Electronic Voting (Richard Celeste, Dick Thornburgh and Herbert Lin, eds. 2006)
Jeff Manza and Christopher Uggen, Locked Out: Felon Disenfranchisement and American Democracy (2006)
Sasha Abramsky, Conned: How Millions Went to Prison, Lost the Vote, and Helped Send George Bush to the White House (2006)
Richard Saphire and Paul Moke, Litigating Bush v. Gore in the States: Dual Voting Systems and the Fourteenth Amendment, 51 Villanova Law Review 229 (2006)