You can translate our tools at Transifex:
Marking strings for translation
Mostly like Django template i18n support, if you have any experience with that.
In python code
from mediagoblin.util import pass_to_ugettext as _
return _(u'This string would tooootally be translatable now.')
If you run buildout it should create a script called 'pybabel'. Use it to extract translations like so:
./bin/pybabel extract -F babel.ini -o mediagoblin/i18n/en/LC_MESSAGES/mediagoblin.po .
./bin/pybabel compile -D mediagoblin -d mediagoblin/i18n/
Pulling translations from Transifex
Unfortunately until the next release of transifex-client which has been patched to have proper entry points, you have to run transifex-client from a virtualenv or from site-packages. But assuming that's done, pulling translations is easy:
tx pull -a
Pushing new translations to Transifex
tx push -s