Just enable the "Disk Mode" feature of the iPod from within iTunes, which will allow you to mount the iPod as a hard drive. Then, you can browse the disk using the Mac's Finder.
Or you can do this in case you can't find it.
On a Mac, you'll need to enable hidden folders in the Finder.
1. Launch the Terminal by going to Applications > Utilities and double-clicking on Terminal.app.
2. Paste in these lines of code:
defaults write com.apple.finder AppleShowAllFiles TRUEkillall Finder
3. If you ever want to make the hidden folders disappear again, just run the code again, but change TRUE to FALSE.
Advanced
Mac users with no fear of using the terminal can do this with a couple of UNIX shell commands:
`mkdir ~/Desktop/frompod find /Volumes/<your ipod name>/iPod_Control/Music/ -name "." -exec cp {} ~/Desktop/frompod\;`
You will need to change <your ipod name> to the name of your iPod, and you'll need to escape spaces with backslashes, i.e.: Joes\ iPod
That find command will dump all the music from your iPod onto a folder called "frompod" on your desktop. You can also use different find command parameters, like date ranges, to extract only some stuff.