GnuCash is personal and small-business financial-accounting software, that lets you track bank accounts, stocks, income and expenses. As quick and intuitive to use as a checkbook register, it is based on professional accounting principles to ensure balanced books and accurate reports.

Here are some of the main features:

• Double-Entry Accounting
• Stock/Bond/Mutual Fund Accounts
• Small-Business Accounting
• Customers, Vendors, Jobs, Invoices, A/P, A/R
• QIF/OFX/HBCI Import, Transaction Matching
• Reports, Graphs
• Scheduled Transactions
• Financial Calculations

GnuCash is available for GNU/Linux, BSD, Solaris, Mac OS X and Microsoft Windows. Get yours here