Make sure the "Manually manage music and videos" check box IS CHECKED on both of your ipods. This will take a little more work but then it will not automatically sync and will easily allow you to connect multiple ipods to one itunes - we have three ipods and one itunes at our place.
same as normal
There's no Ipods which does not work with the new Itunes. However future versions of Itunes may
yes
A third party application for the ipod that downloads only on jailbroken ipods.
You do not Jailbreak iTunes; you jailbreak iPods and iPhones.
1
Yes, iTunes version 9.2 works with all current iPods.
you can only use itunes on ipods
Same as before, through iTunes.
Unfortunately not, however, if your iPod is jailbroken, you can get the Grooveshark app via Cydia.
No, iTunes works exclusively for the iPods.