The IRS issued guidance that bitcoin is to be treated as a property for Federal tax purposes. See more here: http://www.irs.gov/uac/Newsroom/IRS-Virtual-Currency-Guidance

Given the IRS guidance that bitcoin is to be treated as property, donating bitcoin offers compelling tax benefits. Donating appreciated property to charity is an often overlooked tax strategy. It allows taxpayers to deduct donated property that would otherwise be subject to capital gains tax.

Donors should consult with a tax advisor for properly recording this donation on personal tax return.