The Python runtime had been a visible app in the repositories.
The powers that be very recently changed that, so users can't see it.
Apps that need it are supposed to go get it on the sly.
Most of them don't, however.

If you have maemo Extras in your Application Manager list of repositories,
you can go to red pill mode (search and you shall find more info)
and then it will show up as an installable app.
Be sure to go back to blue pill mode after, the matrix is a scary place.

If you are xterm savvy and you have becomeroot installed, you can

sudo gainroot
# apt-get install python2.5-runtime

I hope they change it back. This is a bloody nuisance.