There are a number of other tools you can use to translate WordPress projects, most of them are listed below. Just keep in mind that after you finish your translation, you will need to go to translate.wordpress.org and import the relevant gettext files, as the language packages are built from there.
The Ubuntu Linux project has a web site that allows you to both translate messages without even looking at a PO or POT file, and export directly to a MO. In general, the WordPress projects on LaunchPad are out of date. If you’re working on a current translation of WordPress, be sure to contact the team before making changes to the translation in LaunchPad.
An open source web-based translation system. The server hosted at locamotion.org currently has WordPress translation enabled on it. As with LaunchPad, check with the current translation team before using Pootle.