can i deleted the music from itunes and have it in the ipod touch

If you delete the music from your iTunes Library and then use Sync to manage your iPod, the music will be removed from the iPod as well.

If you use Manually Manage to add music to your iPod, then deleting it from your iTunes Library will not remove it from the iPod - BUT - and this important: you will then have no backup of your music.

You should not rely on your iPod as the only place you have your music.

• If your iPod gets lost, is stolen or it breaks, then you will have lost all your music
• If you need to Restore your iPod (using iTunes), this will delete everything on your iPod, so that too will cause all your music to be lost. It is sometimes necessary to use Restore to get an iPod working properly again
• When you eventually replace your iPod, you will need to have your music ready to go onto your new device. You cannot transfer music directly from one iPod to another one or to a non-Apple device

So you should keep your music on your computer (as the backup for your iPod) and you should backup your computer as well.