1. Create a standard user account
2. Login as this user
3. Personalize the Dock
4. Logout
5. Login with an account that has administrative rights
6. Open a terminal window
7. Execute these commands:

    sudo cp /Users/<user you used at point 2>/Library/Preferences/com.apple.dock.plist /System/Library/User\ Template/English.lproj/Library/Preferences
    sudo chmod 600 /System/Library/User Template/English.lproj/Library/Preferences/com.apple.dock.plist

From now all the new accounts created will use this standard Dock as default.