Some of the most popular software in use on computers is open source. Personally, I would rate Firefox, OpenOffice.org, Gaim, FileZilla, Apache, and Thunderbird to be my favorite open source applications. That doesn’t sound like much, but that’s because I use a lot of freeware applications in addition to the open source software. A free application is not always open source, and more times than not, free programs make the source code unavailable to you. Sometimes it is to prevent people from stealing their code, and other times it is for security purposes (so that people can’t look at the source code to find vulnerabilities).
OSAlt.com provides a great list of open source applications broken up into categories. Initially you might be confused when viewing the software because they do have commercial applications mixed in, but in the upper-right corner you’ll see a drop-down menu where you can select “Open source software” as a filter. That way you see only the open source options for each category.
Another great site that I found is called Open Source Scripts. I would say that this is more useful from a programmer’s perspective because it organizes the open source software by the language it was written in. After you select the desired language, such as C/C++, it will show you a bunch of categories for open source software that has been developed. This can be a great educational tool and an awesome source for help when your trying to create your own program.
Thanks for the tip on OSAlt.com tito!