If you sync with iTunes and get updates through the App store, it is not jailbroken. Updating the firmware will automatically un-break it.
You will not have to pay for them. If the iTouch is truly jailbroken, you don't need to worry about it.
The fourth generation iPod Touch has not been made yet, and there are several other iPods with a fourth generation, so specific information of the iPod is needed to know whether it can be jailbroken or not.
You have to go to jailbreakme.com from your ipod
Restoring an iPod should reinstate the warranty to a jailbroken iPod, unless a problem occurs during restoration, then the warranty isn't in effect since you are trying to restore a jailbroken iPod.
The Jailbroken IPod has Cydia, which "unlocks" or makes your IPod capable of more tasks than a regular IPod.
Yes, you can put music on a jailbroken iPod Touch.
Yes, but it will erase everything on the iPod, including things available only to jailbroken iDevices, such as Cydia, Winterboard, etc. You can then put all NON-jailbroken media back on the iPod by using a backup file of the iPod which is saved on iTunes.
Most of the time if you go to the "general" and the "about" you'll be able to tell.
You get sydia
yes if your warranty is still here and your ipod's not jailbroken.
yes
No, they shouldn't.