All 279 languages are now up, note that clicking on any of those will very likely yield a blank page when you first try it since it'll have to render the world at zoom 2 for that language (unless someone had it rendered already):
http://cassini.toolserver.org/tile-browse/
But some of them are already up:
I came across some encoding problems on the german map: http://tinyurl.com/ngu965
they seem to be better on the english one: http://tinyurl.com/msqlea
but in comparison to the official osm-page they are missing localized names: http://tinyurl.com/mwd64c
i also saw some not-translated country-names. e.g. on http://tinyurl.com/m6rhc5 "Democratic Republic of the Congo" should read "Demokratische Republik Kongo", also "Central African Republic" should be "Zentralafrikanische Republik".
Peter