***Disclaimer*** Jail braking your iPhone or iPod touch will deactivate the warranty on it so if it breaks you will not be given another one free of charge, there is also a small chance that if not done properly some of the apps on your iPod will be deleted- if this happens RESTORE IT.
You can find the tutorial for jail breaking an iPod Here.
Step 1: Using Cydia
There are 5 different sections on the Cydia main page they are: Cydia (home), Sections/ install, Changes, Manage, Search.
In sections/ Install it breaks the apps down into categories games, entertainment, etc. Changes which is just the updates section.
Manage directs you to a page with 3 options to go to- packages (list of your apps).
Sources which you add,
And storage which shows you how much room you have left for new packages. And search, which obviously lets you search for apps.