The latest and the greatest MediaWiki 1.16 is expected to be released someday soon. It's been well over 9 months since 1.15.0, and I'm sure everyone is looking forward to the next quarterly release :P.
There is some time left to complete the translations for this release. All willing to contribute to the MediaWiki localisation are urged to join the localisation effort at translatewiki.net. Below you will find helpful links. Let's make this the best localized version of MediaWiki ever!
Your help is very much appreciated.
* 1.16 untranslated messages (pick your language from the "Language" dropdown and press "Fetch"): http://translatewiki.net/wiki/Special:Translate/core-1.16
* Test MediaWiki 1.16 beta1: http://tr.im/SVxX (tar.gz @mediawiki.org)
* Translation statistics (updated daily): http://translatewiki.net/wiki/Translating:Group_statistics