I would suggest using mac ports...
There is a package called python_select which allows using pythons in parallel. So first install mac ports if not already installed.
First install the python_select package:
sudo port install python_select
Already now you can check which python distributions are available on you system. Just issue the command:
port select --list python (MacPorts 2.x)
python_select -l (MacPorts 1.x)
In my case it printed at least python version which comes by default with Snow Leopard:
port select --show python (MacPorts 2.x)
python_select -s (MacPorts 1.x)
shows the currently selected version, e.g.
python26-apple. So you see, this package nicely plays with Mac. For more options issue
port select (MacPorts 2.x)
python_select -h (MacPorts 1.x)
Than you can search for available python version in the ports repository:
port search python
This will produce a long list will available pythons.
To install the desired packages, e.g. python 2.4 execute:
sudo port install python24
python_select -s will show the freshly installed python as well. To switch to python 2.4 issue:
sudo port select --set python python24 (MacPorts 2.x)
sudo python_select python24 (MacPorts 1.x)
This command is persistent between shells.