Yes all of your data will delete and u should save it to icloud becouse it will start the update and will stp and say connect to iTunes.com
No, itunes supports it.
this will only happen if you choose to update to the newest apple software. updating music and such thru itunes will not touch your jailbreak
If you jailbroke it by using cydia all the apps and cydia apps will get deleted
You can't update iTunes, the only way you can do it is to uninstall it than re-install it.
The short answer is no. There is no current way to manually update itunes. If the automatic update isn't working, uninstall itunes, and download the newest version off of the website.
Update the software in iTunes and it will do it for you.
Plug it into your computer and iTunes will open automatically. If you don't have iTunes download it from apple.com. When iTunes opens you will see under devices your iPhone name will be there. Click that and then press check for update. If there is an update available, download it.
iTunes 9 requires QuickTime 7.6 or later. If you are running an earlier version of QuickTime you will need to update it. The iTunes installing process should let you know if you need an update but will not do it automatically.
New iTunes software can be installed to update the previous version. Only the iTunes software is updated the iTunes library with your music/videos etc. is not affected by the update.
You have to update via iTunes on computer
iTunes
Sync it to iTunes.