How can I delete songs and add new songs

There are two ways that iTunes can be used to delete songs or playlists from your iPod; automatically and manually. The method you use depends on the preferences you chose in iTunes.

Automatically adding and removing songs and playlists

When iPod is set to automatically sync all music with iTunes (default setting), songs and playlists that are added or deleted from your iTunes Library will also be added or deleted from your iPod when the iPod is connected and synced with iTunes. If your iPod is set to only sync certain playlists automatically, songs are added or removed from the iPod when they are added or removed from the playlists in iTunes that are synced to iPod1. For more information about automatic syncing with iPod, see the iPod Tutorials link at the end of this.

Notes

If your iTunes Library contains more than 1,500 playlists, some playlists will not be displayed when setting your iPod to sync only certain playlists.

Manually adding and removing songs and playlists

If you prefer to manage the songs and playlists on your iPod separately from the way you manage them in iTunes, start by setting iTunes to manually manage the content on your iPod.

Next, click the gray triangle icon next to your iPod in the iTunes Source pane. This will allow you to see the contents of your iPod. You can add playlists and songs from iTunes to your iPod simply dragging them to the iPod in the Source pane.

http://www.apple.com/support/iPod/tutori...