First create the catalog if it's not present
$ pygettext.py sources/*.py

Then create your translations with
$ LANG=it_IT msginit

If the code is updated and you have already an it.po you could update the translation
withous losing data with:

$ msgmerge -U it.po messages.pot

If you have finished you could finally create the .mo file with:

$ msgfmt it.po -o it.mo
$ mkdir locale/it && mv it.mo locale/it/
