Make Python25 the default Python Installation

Hello, I've just installed Python 2.5 using Macports. Unfortunately, the system (OS X) still uses Python 2.3.x, which comes installed with OS X, as its default Python installation. I've already tried: sudo port activate python25 which yielded a message saying that that already was the active python version (which is logical, it is the only Python version I installed using MacPorts). Any help would be highly appreciated! L. Holland