Chop for Mac

From zeno.name:

Chop is basically a Cocoa droplet that lets you manage file/folder ownership and permissions.

• Chop lets you recursively modify the permissions of a folder and its entire content, treating the enclosed files and folders INDEPENDENTLY. This means, for example, that with ONE simple drag & drop operation, you could set all the files (enclosed in the folder you drag & drop onto Chop) to be rw-rw-r-(664) and all the subfolders to be rwxrwxr-x (775). In fact it is often requested to give executable privileges to folders and not to files.
• Chop lets you change ownership and permissions of a single file or folder (without modifying the enclosed files). This feature can also be useful as a sort of "Info panel" that shows you at a glance all the attributes (ownership and permissions flags) of the desired file or folder.
• Chop lets you delete all the invisible ".DS_Store" files enclosed in a particular folder, with a single drang & drop operation.

Don't forget to read the online manual to learn how to access these features...