If you have Find My iPhone enabled, you can use Remote Wipe to erase the contents of your device. If you have been using iCloud to back up, you may be able to restore the most recent backup to reset the passcode after the device has been erased.
You need an internet connection to the iPod an computer but not iTunes. You need iOS 5 or later on the computer.
Otherwise you need a computer with iTunes and an internet connection
Forgotten Screen-Lock Passcode
Connect the iOS device to your computer and try to make a backup
Then restore via iTunes. The iPod will be erased. Place the iOS device in Recovery Mode if necessary to allow the restore.
If recovery mode does not work try DFU mode.
For how to restore:
To restore from backup see:
If you restore from iCloud backup the apps will be automatically downloaded. If you restore from iTunes backup the apps and music have to be in the iTunes library since synced media like apps and music are not included in the backup of the iOS device that iTunes makes.
You can redownload most iTunes purchases by: