But the zh interwikis are the worst as there is not only that kind of problems but up to 3 ways to link with 'http://zh.wikipedia.org/wiki/$1': zh, zh-cn, zh-tw.
The problems with the zh: languages are all solved in the pywikipediabot suite.
In short: * zh: links are good * zh-cn: links should be changed to zh: links * zh-tw: links will usually go to a redirect to the corresponding zh-cn: page; if not, they should be changed to zh: links as well.
The pootle web translation portal (and the related open-source Translate toolkit: see its wiki on localization)
Zhengzhu from the zh: wikipedia has developed an automated Traditional<--->Simplified chinese character conversion script, which can be optimized so that it is almost perfect; it reads in a list of phrase conversions to apply on top of its default conversion routine (which is already accurate about 90% of the time).
The Rosetta Project - Help them get audio files, images, and texts from people and languages around the world.