You are not "stealing" by putting 3rd party apps, via a jailbreak, onto your touch/iphone; although you can cross this line with illegal roms, etc, but that is not something you must install; you can avoid those things. Most of these applications are open source, and are free. You are simply bypassing measures Apple has put in place to not allow code not signed by Apple to run; due to their greed, in my opinion....
Depending on which version of the iPod touch that you have, you have a couple of different options.
iPod touch 1g, you can pretty much get a transparent jailbreak, meaning once it is applied, you can restart the ipod and it should boot normally; takes a little bit longer after jailbroken to boot, but this is due to more things happening on boot, and shouldn't be too much of an issue
iPod touch 2g, is still in early jailbreak, and is still "tethered." This means, that you cannot restart the ipod or if it dies, it will require a computer to manually apply the exploit that allows unsigned code to execute on the ipod, ie 3rd party applications and pwned firmware. But once it boots, and you don't allow it to die, this isn't much of an issue. This is only temporary until they find a lower level exploit, but the jailbreak is rather premature and only a few weeks old. If you are not experienced with this sort of thing, I would say that you should wait until a GUI/supported jailbreak is released from the dev team; this is an early unsupported jailbreak.
With that said, from my experience, here are the benefits of a jailbroken iPod touch.
VOIP software, if you are so inclined with getting it functioning.
Custom Boot Logo
Winterboard to customize the look of the ipod; sliders, icons, backgrounds, preferences, labels, etc.
Terminal - you can access the command line on your ipod directly, or via ssh if you so wish, to send commands directly to the iPod Operating System. This can also give you "root" access to your touch, which is comparable to an admin account on a windows machine if you are not familiar with the unix/linux way of doing things. Basically, this gives you full control over the Operating System as you would any other machine running a *nix operating system; you gain many benefits with this, such as the option to install debians apt-get package manager, to name one great added ability.
Access to applications that would otherwise not be available due to app store restrictions; nmap, ssh, terminal, 3rd party application installers, video players, video recording, ported games, game system emulators, roms, ability to sync with multiple itunes collections, it allows you to organize your icons into folders, can add an extra row of icons so you have 5, customize boot logo on the fly, change fonts, remove applications such as stocks etc, allows safari to download files, you can access files on the filesystem, install custom things, write scripts, download torrents, and the list goes on and on. Basically, it gives you full access to your device and its full capacity, rather than what "Steven the ol' Mighty one" has restricted you to.
I own both the iPod touch 2g and 1g, and it is well worth it to jailbreak; opens your ipod/iphone up to a whole new level of uses.