Florian Schulze has created a buildout that compiles Python 2.4, 2.5, and 2.6 on Snow Leopard. By habit, I generally compile my Python interpreters "by hand" so I have a clue what's going on. I really just looked at Florian's buildout to see what it did and did that by hand.
Here's what I had to do to get Python 2.4 compiled on a fresh Snow Leopard install (not an upgrade) on a 32-bit Mac Book Pro (a Core Duo, not a Core 2 Duo; those have other issues).:
CC="gcc -I/sw/include -L/sw/lib" ./configure MACOSX_DEPLOYMENT_TARGET=10.6 --disable-tk --prefix=$HOME/opt/Python-2.4.6
CC="gcc -I/sw/include -L/sw/lib" MACOSX_DEPLOYMENT_TARGET=10.6 make install