OpenAccounting is a free, open-source, easy-to-use, web-based Accounting and Inventory System.
OpenAccounting is in active development and is currently in Beta.

Main Features :

Sales - unlimited customers, customer branches, invoicing, credits, payments and refunds, sales areas, sales types, sales persons, shipping companies.
Purchasing - unlimited suppliers, supplier price lists, different payment terms.
Items and Inventory - inventory and non-inventory items, item categories, inventory locations, adjustments, location transfers, reorder levels.
Manufacturing - Bill of materials, work centre tracking, advanced work order entry
Projects - project due date and cost tracking.
Banking - Multiple bank accounts, detailed payment and deposit, currencies, exchange rates, bank inquiry and reports.
General Ledger - unlimited accounts, account groups, manual journal entry, detailed inquiry and reports.
Access and Customization - Multi-user access with different priviliges, transaction voiding, transaction reprinting, backup and restore, multiple taxes.

Advanced Features :

Advanced taxation : Multiple tax definition with tax group, definition of inclusive taxes, taxes can be selected per customer, per supplier and per item.
Full multi-currency support : Historical exchange rates, multi-currency bank acocunts, customers and suppliers.
Multi-language ready : Full support for localization utilizing GNU's gettext package.