A while back I wrote some anti-plagiarism software. It compares all the documents in a folder against each other for evidence of copying. The feedback is that it needs to be able to accept more file formats, in addition to plain text (.txt) format, in particular Microsoft Word documents. So I've made a free utility that can batch convert files from doc to txt format. Popular software source files such as .cpp, .java (and many more) can now also be checked.
Download and try it out here.