I've published my & j00ru's entropy measurement tool called Ent (version 0.0.3, still alpha, but works). One can read about it and download it (with source code, BSD-Style license) here:
http://gynvael.coldwind.pl/?id=158

An article (blog post in fact) about how it works with some commented entropy charts can be read here:
http://gynvael.coldwind.pl/?id=162

A sample chart generated by Ent:
http://gynvael.coldwind.pl/img/ent_final.png


Btw, I wanted to add this tool to http://www.woodmann.com/collaborative/tools/, however, I have no idea in what category to place it. Any idea?

Nice tool.

I've created a suitable category for it and added it to the CRCETL, here:

http://www.woodmann.com/collaborative/tools/Ent

If you have a tool that you think there is no suitable category for in the CRCETL, please simply add it to the "Needs New Category" category (http://www.woodmann.com/collaborative/tools/Category:Needs_New_Category), and it will be taken care of.

Thank you dELTA ;>

interesting stuff, why don't you also allow output in csv form, or even incorporate a graph control like this:http://www.codeproject.com/KB/miscctrl/oscope.aspx
I have a greatly modified version of this control which also fixes a lot of memory leaks and adds some features. If you like I can give you the code..

I recently needed a tool like this. Very nice contribution! Looking foward for the future releases.