If you jailbroke it by using cydia all the apps and cydia apps will get deleted
yes
You get sydia
Not without erasing the jailbreak.
you must restore itouch then update. Sorry!
The iPod Touch should not delete things when you update it. All content should remain on the iPod (unless you have a jailbroken iPod, in which case it will remove all non-App Store apps and other jailbroken features).
you can't
Yes and no. If you sync it your iPod will remain jailbroken. If you update it to say 4.1 it will un-jailbreak your iPod. Then you will need to re-jailbreak it.
Yes but you will lose all the jailbreak features.
you cant anymore
if you want it to be jailbroken then no,if not yes
Unless you want to brick it, don't. Wait until there's an update to your "Jailbreak" and then update. BE SURE TO UNJAILBRAKE YOUR IPOD BEFORE UPDATING!!
You have to go to jailbreakme.com from your ipod