I came across this tool today, and while innately simple, is something very useful and not so obvious to most. As a strong supporter of Linux, one of the biggest complaints I hear from people trying to switch is the unfamiliarity with the veritable horde of software choices a Linux desktop offers. While someone may be computer saavy and not afraid to learn, if you don't know the software exists it won't do you any good. Some may be quite obvious with a preinstalled desktop, but a typical desktop user may use 20 different programs in a day without thinking about it. To help ease the transition, a project called the "Linux Equivalent Project" has been built. It is a constantly evolving list that takes some of the most popular software packages for Windows and shows you some of the most comparable alternatives.
While just a tiny list at the moment, the idea is a good one. I hope the author continues this project and expands the list further. You can read the list yourself at the project website.