Like they say, there are many ways to skin a cat. In Ubuntu, there are at least five ways to figure out what version you are running on your system. From the Gnome Menu, you can navigate to System>About Ubuntu. This is by far the easiest. There are alternative ways of course. From the Terminal, you can type one of the following:
$ uname -a $ lsb_release -a $ cat /etc/apt/sources.list $ cat /etc/issue
If you know of other ways, please leave a comment.