I connect my iPod and iPad to my computer to charge them. I do not want them to automatically mount on the desktop.
How can I keep using my computers many USB ports for charging without being bothered by auto-mounted devices?
The con is that you won't be able to mount your device without removing the rule...
To enable or disable automount open a terminal and type dconf-editor followed by the [Enter] key.
Browse to org.gnome.desktop.media-handling.
The automount key controls whether to automatically mount media. If set to true, then Nautilus will automatically mount media such as user-visible hard disks and removable media on start-up and media insertion.
There is another key org.gnome.desktop.media-handling.automount-open. This controls whether to automatically open a folder for automounted media.
If set to true, then Nautilus will automatically open a folder when media is automounted. This only applies to media where no known x-content/* type was detected; for media where a known x-content type is detected, the user configurable action will be taken instead. This can be configured as shown below.
Taken directly from the ubuntu help page.