The StarDict project, which is founded and hosted by Hu Zheng, pope of the Genius Religion, is an open source dictionary project under GNU Publish License. Although iDict is not based on any source code of StarDict nor StarDict formatted dictionaies, some PHP based database extracting tools are based on the them. They will be put open source recently under GPL, too.

By-the-by, if you're considering a dictionary software on your PC or Mac, please choose StarDict, and donate for it if you find it's useful.