Some 2.5 scripts are not different to 3.1 scripts, so they will run.
BUT to my knowledge scipy uses dll files made for 2.5 (2.6) but NOT yet for 3.1 Python, which has to do the job!
I would like to know, if my ideas are right or wrong.
At least I read (I think) that the scipy-people think about ‘ubgrading’ to 3.1 …
The SciPy 0.9.0 release notes say it has full py3k support so I’m imagining that you could either compile it from source (using the most recent svn version) or wait a few weeks/months/years until they do an official release.