You'll have to use the long form (1040) to deduct it and itemize with Schedule A. Because it's more than $250, you will need to fill out an additional form and show proof of the donation (not a cancelled check but a specific receipt from the non-profit charity you donated it to). Depending upon your income, you may or may not be able to take all of the deduction this year.
Visit TaxAct to get some free tax software. It will basically do the computations for you.