The jailbreak will allow you to do the following things that you cant do on a non-jailbroken IDevice:
*Download and install themes.
Themes are downloaded from the Cydia program. Cydia is installed when your IDevice is first jailbroke.
Themes can be used to add backgrounds to your home and lock screen. Your lock screen will also have a custom scroll unlock bar that is set with the theme you have chosen. Your icons on your home screen will be changed with the theme you have chosen also.
*The jailbreak allows you to download and install apps for free that the IStore charges for.
*You can download and use any ringtone that ITunes charges for and you will be able to use these ringtones without the use of ITunes.
*One of the bad things about the jailbreak and I will be honest is that it voids the warranty on your IDevice. But do not fear because if for some reason you did not like the jailbreak or need the jailbreak removed for your GSM to do anything about your IDevice then your IDevice can be restored to factory standards and the GSM will never know it was ever jailbroken.
*If the jailbreak has been removed from your IDevice then I can put the jailbreak back on your IDevice for the price listed.