For more details about easy_install support with multiple versions of Python check out Multiple-Python-Versions found at packages.python.org.
As of version 0.6a11, EasyInstall
installs itself under two names:
easy_install and easy_install-N.N,
where N.N is the Python version used
to install it. Thus, if you install
EasyInstall for both Python 2.3 and
2.4, you can use the easy_install-2.3 or easy_install-2.4 scripts to install
packages for Python 2.3 or 2.4,
Also, if you’re working with Python
version 2.4 or higher, you can run
Python with -m easy_install to run
that particular Python version’s
Basically, easy_install and setuptools install libraries to the version of Python that is being used to run them. So it sounds like 2.4 is the version of Python being used when easy_install/setuptools is run. See the following question/answer on ServerFault: easy_install'ing under different Python version
It's possible that you could setup (or modify) a symlink for
/usr/bin/python to point to the python install (2.6 I would assume) that you would like to use by default.