Freeware, cross-platform, for OS X 10.3 and above (Java) Chinese language tool that includes a dictionary, stroke reference, annotator, and much, much more. Look up Chinese characters by English, pinyin, radical/stroke, and Cantonese.
DimSum is an instant-lookup text reader, with support for adding romanization to text files, RTF files, and HTML pages.
Also includes an array of miscellaneous tools, including an abacus, flashcards, Chinese name generator, GIF creator, and various converters for currency, measures, numbers, romanizations, and encodings.
Chinese Text Annotator - Break a text into words and add links to dictionary entries.
Study Chinese characters with Java flashcards, repair corrupted Chinese e-mails.
Convert files between GB, GBK, Big5, UTF-8, UCS2, and CNS