The Plug and Play driver project for Linux is a project to create support within the Linux kernel (see Linux.Org for more information) for handling Plug and Play (and other semi-PnP) devices in a clean, consistent way. It aims to allow a driver of any type of hardware to have this hardware configured by the PnP driver in the kernel. This driver is then notified when the device is reconfigured, or even removed from the system, so as to allow for graceful action in these circumstances http://www.io.com/~cdb/mirrors/lpsg/pnp-linux.html .
ISA PnP tools is another useful package.
And there is a project at RedHat http://www.redhat.com/pnp/overview.html .
The latest PCMCIA driver package (>>3.1.0) has utilities lspnp and setpnp to manipulate PNP settings.