GnuCash allows you to 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. It is backed by an active development community and is blossoming into a full-fledged accounting system.
QHacc is a personal accounting program based on Qt. It features double- or single-entry bookkeeping and a reconciliation window. It also provides support for memorized and split transactions, graphing, reporting, archiving, and scheduled transactions that can be based on the account balance.
GNU Radius is a RADIUS server and an accompanying set of monitoring utilities. It features MySQL and PostgreSQL interfaces for authentication and/or logging (the ODBC interface allows you to use almost any existing DBMS for that purpose), the ability to rewrite RADIUS requests from various NASs to normalize them to a more understandable format, and the ability to completely customize the behavior of RADIUS authentication and accounting based on NAS and user attributes.
rimric interactive offers complete intranet/Internet databasing and collaboration solutions for any sized business or project. You can maintain invoices, purchase orders, contacts, investment groups, securities, and other data sets, or establish a Wiki based on standards, all using the fastest technologies available.
Pavin' The Way's is an accounting system that includes four distinct modules: Supply Chain Management, Sales Chain Management, Accounting, and Warehouse Management. By completely integrating these processes within one, easy-to-manage system, it ensures that you will have a complete road map of where and how your products are moving. It works in real time, giving you up-to-the-second statistics.
FreeCoins is an accounting program written in C++ for PalmOS. It features multiple accounts in multiple categories, scheduled/recurring transactions, split transactions, a proper (collapsable) account tree, double entry bookkeeping (similar to GnuCash), cleared/uncleared transactions, separate cleared/uncleared balances totals for the current account, current category, and all accounts in all categories, and the ability to add/delete/modify accounts and transactions to suit your needs.