I have a problem of upgrading python from 2.4 to 2.6:
I have CentOS 5 (Full). It has python 2.4 living in /usr/lib/python2.4/ . Additional modules are living in /usr/lib/python2.4/site-packages/ . I've built python 2.6 from sources at /usr/local/lib/python2.6/  . I've set default python to python2.6 . Now old modules for 2.4 are out of pythonpath and are "lost". In particular, yum is broken ("no module named yum").
So what is the right way to migrate/install modules to python2.6?
easy_install is good one but there are low level way for installing module, just:

unpack module source to some directory
type "python setup.py install"

Of course you should do this with required installed python interpreter version; for checking it type:
python -V
Transition from Python2.4 to Python2.6 on CentOS, module migration problem