A Python3-compatible version of BeautifulSoup is now bundled with the Python2 BeautifulSoup tarball. It's actually been available since 27 December, but the most recent version 3.1.0.1 addresses a bug in attribute handling.
It's a bit fiddly to get it working---you need patch, and both python3 and 2to3 on the command line (and 2to3 to be called 2to3-3.0---but when it does so, that ol' BS magic is pretty clear. While there's still lots of good reasons not to convert all your Python2 code to Python3, there's now one less reason not to begin your next big project in Python3.
(BeautifulSoup has an active user group on Google Groups, so you can report any bugs there.)
