Here is some material on Charitable contributions and tax deductibility. Please understand that nothing we provide should be considered or should substitute for appropriate legal advice.
http://www.hurwitassociates.com/l_qa_charitablecontributions.php
http://www.labyrinthinc.com/SharedContent/SingleFaq.asp?faqid=44
http://www.sumptionandwyland.com/faq/charitable_deductions.html
http://nonprofit.about.com/od/fordonors/tp/taxdeductionsforcharity.htm
There is a variety of material on the IRS site.
http://www.irs.gov/pub/irs-pdf/p1771.pdf
http://www.irs.gov/charities/charitable/article/0,,id=123204,00.html
http://www.irs.gov/pub/irs-pdf/p561.pdf
http://www.irs.gov/pub/irs-pdf/p526.pdf
http://www.irs.gov/pub/irs-tege/pub4302.pdf
More
http://www.boardsource.org/Knowledge.asp?ID=3.135
http://www.nonprofitlaw.com/fund/gift.shtml
http://nplawcast.com/2008/10/nonprofit-law-podcast-46-charitable-receipts/