http://translate.google.cn/translate_a/t?client=t&text=你好&hl=zh-CN&sl=zh-CN&tl=en&ie=UTF-8&oe=UTF-8&
http://www.crifan.com/teach_you_how_to_find_free_google_translate_api/
当然因为墙的原因，也可以试试：
http://developer.baidu.com/wiki/index.php?title=%E5%B8%AE%E5%8A%A9%E6%96%87%E6%A1%A3%E9%A6%96%E9%A1%B5/%E7%99%BE%E5%BA%A6%E7%BF%BB%E8%AF%91/%E7%BF%BB%E8%AF%91API