The below information is for general reference and not intended to replace the advice of a legal or tax professional.

The following is a list of useful publications from the IRS.

Form 990 Resources and Tools

Compliance Guide for 501(c)(3) Public Charities, IRS Publication 4221pc: Download Document Compliance Guide for 501(c)(3) Private Foundations, IRS Publication 4221pf: Download Document 

Charitable Contributions, IRS Publication 526: Download Document 

Charitable Contributions: Substanciation and Disclosure Requirements, IRS Publication 1771: Download Document

Substantiating charitable contributions article from the IRS

Specific to Noncash and Property Donations

Noncash Charitable Contributions, IRS Instructions  for form 8283: Download instructions

Detemining the Value of Donated Property, IRS publication 561: Download Document

A Charity's Guide to Vehicle Donations, IRS Publication 4302 : Download Document