You can transfer information and files between your iOS devices and computers, using iCloud or iTunes.
iCloud stores your photos, apps, contacts, calendars, and more, and wirelessly pushes them to your devices, keeping everything up to date. See iCloud.
iTunes syncs music, video, photos, and more between your computer and iPod touch. Changes you make on one device are copied to the other when you sync. You can also use iTunes to sync files and documents. See Sync with iTunes.
You can use iCloud or iTunes, or both, depending on your needs. For example, you can use iCloud to automatically send the photos you take on iPod touch to your other devices, and use iTunes to sync photo albums from your computer to iPod touch.
Important: To avoid duplicates, keep contacts, calendars, and notes in sync using iCloud or iTunes, but not both.
You can also manually manage content from iTunes, in the device’s Summary pane. This lets you add songs and videos, by choosing a song, video, or playlist from your iTunes library and then dragging it to your iPod touch in iTunes. This is useful if your iTunes library contains more items than can fit on your device.
Note: If you’re using iTunes Match, you can manually manage only video.