Translation service world wide
Articles needing translation
Category:Articles needing translation from foreign-language Wikipedias contains all articles that have been tagged to suggest that they be expanded with content from another language's Wikipedia translated into English. Browse the appropriate language category to find an article you are interested in.
Tools like this one can locate articles that may need translation by finding foreign-language articles with no interwiki link to English, but interwiki links to several other languages.
License requirements
A translation is a derivative work. Wikipedia articles are under a copyleft license that requires attribution to the original source and authors in all derivative works. How to do this is described in Help:Translation.
Translation to other languages
Translations of an article on English Wikipedia into some other language are covered at Wikipedia:Translate us.
For translations between two non-English languages, see the versions of this page in one or other of those languages – each Wikipedia has its own standards and conventions for such translations.