These wiki pages have been set up to help Xfce translators from all over the world to work on translating Xfce.
What can you do here? Manage a team with a list of current translators for your language and keeping a dictionary of uncommon words. But also get some quick help and first-starter guides for translators.
Transifex (alias Tx) is the platform for translators and project maintainers installed at transifex.com. It gives the possibility to edit/upload translations through a simple form instead of learning technical tools. The "Get involved" page gets you indications about the registering process, team work, and downloading/uploading translations.
The list of teams contains the maintainers of each language. Don't be shy to insert the team of your language (even if you are the only translator), that can only make it more friendly for new translators to join in. You can have a look at the other teams pages to get an idea about what you could put in yours. If you are using an external resource to exchange discussions and keep web pages like the Google Groups, then simply put a link on the teams page.
There is the Daichi's translation guidance into Xfce. There is a list of softwares to use for translating. And there is a list of languages and language codes to use for the PO filenames.