Moodle - Moodle is the world's most popular learning management system. Start creating your online learning site in minutes!
Invoice Ninja - Invoice Ninja is a free, open-source solution for invoicing and billing customers.
Chamilo - Chamilo is a software that allows you to create a virtual campus for the provision of online or semi-online training.
Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.
Edmodo - Where Learning Happens
GnuCash - A personal and small-business financial-accounting software, licensed under GNU/GPL and available for Linux, Windows, Mac OS X, BSD, and Solaris.