All iPod apps are from iTunes.
no you cannot use ipod and iphone apps on itunes, but you can buy the apps on itunes and put them on your ipod and iphone
Yes
Nope, no sharing apps.
You can connect to a wireless router and use the App Store app to browse and download applications directly to your iPod Touch via the Wi-Fi connection without connecting to your computer.
Yes, but downloaded apps from Installous will not sync with iTunes.
The iPod Nano does not use apps.
You buy apps at itunes.
The iPod Nano cannot use apps.
Yes, it doesn't matter what iTunes software you have, you can still download apps from it to download to the iPod Touch.
you need an ipod touch or iphone :)
First download the apps onto your computer using iTunes. Plug in your iPod to your computer, open iTunes, and set the sync settings so that you can download apps to it, sync your iPod and you should see the apps on there. This requires an iTunes account.