RedHat/CentOS – How to Install Python 2.5

Yep, just build your own python and put it somewhere else (something like /opt or /usr/local). You'll need to rebuild mod_python, when you do you can specify the new python location.

./configure --with-python=/path/to/python2.4

Last time I played with different versions of python (at least a couple of revisions back so this may have changed and on Debian so with other distros YMMV), when compiling and installing from source you can do make altinstall instead of make install. This creates just a pythonX.Y binary and does not touch any current python binary. This way you get he right version by running, say, python2.6 (or using #!/usr/bin/python2.6 at the head of a script) but if just python is specified the previous default is used. As the standard libraries are usually separated by version they should not conflict, though you may need to tweak your command and library search paths in some cases and some third party modules might need some alteration to install in the non-default place.