I just install OS X 10.6 (Snow Leopard) in my iMac. Python 2.6.1 is installed automatically with X Code, however I found a problem with virtualenv.

After install virtualenv by command:

$ sudo easy_install -Z -O1 virtualenv

And try to create a new virtual environment:

$ virtualenv myenv1

It just freeze and use 100% on one of my dual core. After google for a while, I found this solution:

$ sudo easy_install -Z -O1 http://bitbucket.org/ianb/virtualenv/get/tip.zip

Then everything working like a charm. (The cause of this problem is easy_install was trying to install from the SVN which didn't contain fix patch for Snow Leopard yet.)