Created in 2007, the Software Development Tools Directory has now more than 1500 references. It is one of the rare web sites where you can see on the same location both commercial and open source software development tools. Tools are categorized by programming language, license, operating system or software development function (software testing, project management, database, IDE, user interface, etc.). The Open Source category is the most important one with 770 tools. http://www.softdevtools.com/