XLIFF (XML Localisation Interchange File Format) is in the process of becoming an OASIS standard. But what is XLIFF? The FAQ will help us.
Why XLIFF? XLIFF addresses the following localisation challenges:
Insufficient interoperability between tools.
Lack of support for overall localisation workflow.
Necessity of localisation tools developers to deal with many formats.
Large number of proprietary intermediate formats.
And XLIFF offers
Single format for adjunct processing (e.g. quality control in terms of spell checking).
Tighter control on what goes to localisation (Pre-filtering of what to translate or not).
Controlled information flow (author/developer notes, item properties, etc.).
Identifier-based leveraging.
All advantages of XML-based processing.
All right, XLIFF is technically better than PO, but do we have free mature XLIFF editors?
Heartsome XLIFF editor is not free, in spite of Rodolfo M. Raya's cooperation with free software projects.
Then we have Freedesktop.org's XLIFF Tools Project, which provides a pair of xliff <-> po converters, Asgeir Frimannsson's xliff-po-tools and Rodolfo M. Raya's xliff-tools-java)
Transolution (was EvilTrans) + Fredrik Corneliusson's XLIFF filters: sgml2xliff.py for docbook, html and Staroffice/Openoffice files
«State: The Editor is ready for basic translation of XLIFF documents. At present it only supports a subset of the XLIFF standard and is not guaranteed to work with XLIFF's in the wild. The major features missing are full XLIFF compliance, tag verification, spell check and overall polish.»
Since June 2005 (sic) we have Sun's Open Language Tools (Open Language Tools XLIFF Translation Editor and Open Language Tools XLIFF Filters).