Nonprofit Accounting Software
GNUCash appears to be the best FLO accounting option but doesn't have all the features needed for nonprofit accounting.
How to donate money to gnucash: http://wiki.gnucash.org/wiki/Development
Development wish list for GNUCash: http://wiki.gnucash.org/wiki/WishList
Google Docs Accounting Template: https://drive.google.com/templates?q=non+profit+accounting&sort=hottest&view=public
Research
Useful overview: http://209.190.249.70/content/index.php?pid=154
How to classify different types of gifts: https://www.utdallas.edu/finance/main/procedure-gift.html
Current vs. Non-Current: http://simplestudies.com/difference-between-current-and-noncurrent-assets-liabilities.html
Cash vs. Accrual: http://www.nonprofitaccountingbasics.org/accounting-bookkeeping/cash-vs-accrual
Employees or Independent Contractors: http://www.bizfilings.com/toolkit/sbg/tax-info/payroll-taxes/employee-or-independent-contractor-payroll-tax.aspx
Charging "Program Service" Fees: http://fiscalissues.blogspot.com/2008/01/program-service-fees-for-nonprofits.html
Differences between Nonprofit and For-Profit Accounting: http://www.resources.blackbaud.com/nonprofit-financial-management/differences-between-nonprofit-and-for-profit-accounting.html
Status Update
Mike Linksvayer:
"LWN (LinuxWeeklyNews) has an ongoing series of articles (so far Ledger and PostBooks) about their quest for free software accounting. Their use case is a small business, but much is still pertinent. Also, I'm reasonably sure there will be an organized initiative to improve free software accounting packages for the non-profit use case later in 2013."