Entropy Estimator

I just added a feature to my entropy graphing program that estimates the number of bits of entropy in the file, in addition to making the graph. I tested it on some ZIP files, comparing the sum of the results obtained from each file individually to the results from the ZIP file containing all of them. So far, the results have been consistent within 20%. EXE's show 3-4 entropy bits/byte, ZIP files show 6-7, and DLL's and text files show 1-2. Source code (Visual Basic) available to anyone who wants it, but I think I will hold off on the EXE and VBX's until I find someone who will put it on their FTP/WEB site. Suggestions via email regarding this would be appreciated. Jonathan Wienke