Arch Linux

Description:
I quote "If you're using Python 2.3 through 2.6, the 3.0 series is the best choice. The most recent release in the 3.0 series is 3.0.8.1, released April 9, 2010.

If you're using Python 3.0, you must use the 3.1 series. Beautiful Soup version 3.1.0.1 was released January 6, 2009. You can use the 3.1 series with earlier versions of Python, but you might run into the problems described here. (I consider the 3.1 series a failed experiment and will eventually be replacing it, but it's here if you really need it.)
"

More explanation of the problem on the page http://www.crummy.com/software/BeautifulSoup/3.1-problems.html

one quote on this page is:
"The 3.1 series has been abandoned. The 3.0 series is still under development; use it instead. To avoid confusion about which version of Beautiful Soup is "the latest", the 3.0 development will soon be called the 3.2 series."