Among the many minor changes included in version 3.0 of the iPhone OS, there is one that allows the many compatible iPhone accessories to work more closely with a specific application. Even better, when you connect one of these devices, a notification will prompt you to download the dedicated application for the device in question. What you can obviously refuse.
This kind of situation is likely to happen with the imminent availability of the TomTom car kit.
We discuss it on the forum.