According to a July 2011 article by ASCAP contributor Chris Castle, Kickstarter monies are likely to be taxable for many artists. 

Castle's analysis starts with the presumption that you aren't a non-profit and that you have entered into some kind of contract with your contributors, like, "If you give us money, we'll give you X ."  Castle believes that as a result of entering into this contract, you may owe self-employment tax, sales tax, and other taxes.