gtkdocpo is a tool to create a pot file from C source files that used gtkdoc to generate API documents, and to merge the l10n po file to the C source files.
py-autopotools is a tool for i18n and l10n which automates a lot of the common tasks performed on po files. Create new files, delete or merge comments, file positions, and translations seperately, create default translations - pocreate does it all.