There are countless arguments for using open source applications, but one of the strongest is having a single interface to learn when working on Windows, Mac or Linux systems. Web site directory Open Source Living helps you find just those kind of programs. It's not an extensive, all-in-one directory, but it seems to narrow its choices based on quality and widespread acceptance. And while not every application listed at Open Source Living is entirely cross-platform, a good deal of them are. For more free or open source applications.