kivitendo, formerly known as Lx-Office, is a Web-based accounting system tailored for the German market (e.g., tax calculation). It can export accounting data in the German DATEV format and features invoicing, sales orders, quotes, etc. Forms are generated on the fly as PDF or OpenDocument documents.
cclite is a lightweight implementation of a community currency registry for local exchange trading systems (LETS) and other alternative money systems. It uses multi-registry, multi-currency, Web-services-based (SOAP) transactions, and is templated to give multi-lingual properties. As of 2009, it has an SMS interface and versions for Debian, cpanel-based, Fedora and Windows XP. As of 2012 it has decimal currencies, templates for many languages, and a REST-style interface for integration with CMS and social networking software.
File2Radius is a daemonized script that tails a CDR accounting log file and generates RADIUS accounting records on the wire from it in real time. It was designed to be used with the Broadsoft soft switch, but could be adapted for other sources of CDR data. It supports sending to a primary and backup RADIUS server and automatically follows log files as they are rotated. The script assumes that you are performing duplicate checking on the RADIUS server backend. It supports the loading of bulk archive data with 'fake' source IPs.
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.
ASTPP is a billing solution for Asterisk and FreeSWITCH. It supports pre-paid and post-paid billing with call rating and credit control. It also provides many other features such as calling cards, least cost routing (lcr), did management, resellers, callbacks, etc. ASTPP is able to integrate with OSCommerce to provide a Web store for your users to purchase calling cards and sign up for VoIP accounts.