Opensource

http://www.greensql.net/ SQL-proxy/filtering software for MySQL and PostgreSQL databases, used to prevent SQL-injection-like attacks, filter-out dangerous SQL, etc

http://bigbluebutton.org/content/videos opensource web-conferencing software, something like GoToMeeting, allows sharing voice, video, presentation and desktop

http://www.argentuminvoice.com/ open source client-management and invoicing software

http://jeremy.zawodny.com/blog/archives/010511.html notes on existing open source queue/messaging systems

http://wix.sourceforge.net/ tools to build MSI packages based on XML scenario files

http://racktables.org/ “Racktables is a nifty and robust solution for datacenter and server room asset management. It helps document hardware assets, network addresses, space in racks, networks configuration and much much more!”

http://mzz.ru/ kind of cool MVC framework, supports a lot of modern features like url routing, etc. documentation seems to be only available in russian

http://www.osdbzine.net/ pdf magazine that covers open-source databases, MySQL, PostgreSQL and alike.

http://zooie.wordpress.com/2009/07/06/a-comparison-of-open-source-search-engines-and-indexing-twitter/ this is not a strict benchmark, but rather a broad review. Results should be taken as a starting point in research, not as benchmark results.

http://karesansui-project.info/wiki/karesansui/En_tutorial web management for XEN, including installing, monitoring and console. Based on libvirt, written in python, ,uses JQuery for interface, tightvnc-java for console, SQLite [default], MySQL, PostgreSQL as database.