No site mashable.com/ achei uma lista enorme de aplicações open-source, vale a pena conferir, achei várias que nunca tinha ouvido falar.
Segue uma pequena lista
FrontAccounting – A professional web-based accounting system for ERP chain; written in PHP with use of MySQL.
bbLean – A new version of Blackbox for Windows.
CyGNOME – A nice tool which ports GNOME desktop to Windows.
Sylpheed-Claws – An open source email client with an interface similar to Outlook Express; works as an RSS feed reader too.
Thunderbird – A secure email client with several customization options to fit the user’s needs.
Clique aqui e veja a lista completa.
