Localisation and internationalisation for MediaWiki is done at translatewiki.net. We have always called it Betawiki, but it proved to be a source of confusion. The name of the project does not have a relation to the URL.
It is for this reason that the admins of translatewiki.net have decided to abandon the Betawiki name. This blog has many articles referring to this project. All the articles have been given a new label.
This is just a name change. Effectively nothing changes; we will continue to rely on your help in making MediaWiki insanely great for all the languages that need localisation.