Can a business receive a tax-deduction for an in-kind gift?

Summary:

Yes, but in many cases, such gifts are treated as business expenses, which is often simpler and just as effective for the donor.

Someone wrote in NONPROFIT (see http://www.rain.org/mailman/listinfo/nonprofit) in April 2004:
I want to hold a special event with items donated by local business and since we are a 501(c)3 organization, will the value of these itmes be tax deductible for the donors?

Robert Shriner of the Shriner-Midland Company in Falls Church, Virginia, replied on April 27, 2004:
Donations by businesses to a charity are not usually treated as a
tax-deductible charitable contribution but as a deductible business expense
(for marketing, promotion, etc.). In some cases, larger corporations may make
charitable contributions from profits; but more frequently small and medium
sized firms simply treat the donation amount as a business expense. Offering
them 'tax deductibility' therefore isn't much of an incentive to a business to
make a donation. If they are persuaded of your cause and see an opportunity to
get visibility for the company or its products/services through a donation,
those are the factors that will result in donations.

Also, as Tony Poderis points out (see http://www.nonprofits.org/npofaq/18/80.html), your organization cannot set the amount nor provide a guarantee that a donation will be tax deductible. It is the responsibility of the donor to provide independent valuation of donated goods, services, works of art, etc., that may be needed to satisfy IRS.