The first set of language packs for Project Server 2010, and SharePoint 2010 and the other family members, have now been posted up to the Download Center at http://www.microsoft.com/downloads/details.aspx?familyid=046F16A9-4BCE-4149-8679-223755560D54&displaylang=en. As for Project Server 2007 there are some that work for SharePoint Server 2010 and Project Server 2010, and a few that are not supported by Project Server 2010. Unsupported just means that you will not get the language you might be expecting – but in the short term you should also avoid these unsupported ones until we fix an issue we found just before RTM. If you have an unsupported language (Thai and Hindi, from the current – as of 5/12 – list) installed then Project Server will not be able to upgrade a set of Project databases from 2007 to 2010. If you are already up and running then you shouldn’t have any problems, and the next time you need to upgrade the databases will very likely be when the fix is part of that upgrade (early CU, which will also be rolled up to the Service packs).
The other good news is that they are exe and not iso this time – but all called ServerLanguagePack.exe, so if you are downloading a few you might want to rename.
For the full list of languages supported and not supported, see Overview: Project Server 2010 with SharePoint Server 2010 Architecture.
There will be a full TechNet article on the installation of Language Packs for Project Server 2010 coming in the next few weeks – I will update with a link when it is available.
***Update*** and here is the link http://technet.microsoft.com/en-us/library/ff700192.aspx . You should note that although we list Portuguese and Brazilian - the Language pack is actually Portuguese (Brazilian).
***Another Update*** SharePoint have added Basque, Catalan and Galician language packs. None of these are supported for Project Server, but like the other 'non-supported' ones, they are compatible.