Start->Control Panel->Hardware and Sound->AutoPlay
Windows 7's AutoPlay is content-specific and device-type-specific instead of just device-specific.
They DO have a "Devices" section at the bottom of the mentioned AutoPlay setup screen, but "Removable Disks" (aka "volume devices") don't reflect there, as it's for more-specific devices (like, hopefully, your iPhone). "Volume device" AutoPlay is determined by the content on the volume.
What would keep a device from appearing under "Devices" in AutoPlay?
If you have connected a volume device to your computer (for example, a USB flash drive or external hard drive), that device will not appear in the Devices section of AutoPlay. AutoPlay only lists non-volume devices (for example, some digital cameras, video cameras, and phones). This is because these devices don't use a standard file system and AutoPlay cannot browse the contents of these devices to see what types of files they contain.
More info here.
Hope that helps...