How do I zip a folder on the iPhone

I have seen a lot of related questions but none really helped. I'm trying to create a zip archive from a folder (on the iPhone).

The structure of the folder is the following:

In this example the zip would be "folderToBeZipped.zip" What is the easiest way to accomplish this and how do I unzip it (also iPhone) later on?

Maybe you can find this project useful

http://code.google.com/p/ziparchive/