GPL v2 was released in 1991, two years after the release of the first version of the license created by Richard Stallman, FSF founder, to protect his GNU operating system project from turning into a proprietary project.More details over at Internet News.
While he didn't invent the word, Stallman popularized the notion of "copyleft," which ensures the original software as well as derivatives are free and can be freely modified. The GNU GPL is the specific implementation, according to the GNU Project's Web site, of copyleft.
GPL 3 is coming closer

An updated version to the General Public License (GPL) is coming a little bit closer as the Free Software Foundation (FSF) and Software Freedom Law Center (SFLC) released a new process definition document this week, outlining the course they will take to shepherd work on GPL 3.