Here is the one I have been using for the last couple years:
HashCheck Shell Extension
http://code.kliu.org/hashcheck/
It is a shell extension for Windows Explorer. But it can also generate a hashcheck file that can be used for verification. If the target is a different path you can just edit the file. Double clicking on the file launches the verification.
It is Windows only, but it is Open Source. It is not near as complete as the Corz software appears to be, but it works for me.