MEV Altera Cyclone IV PCIe Reference Design Kit

As for writing windows drivers I'm unable to help you there since my application is embedded ARM based and others have the responsibility of writing the drivers for our OS (proprietary).

If the microcontroller is an SPI slave, this should be almost trivial since you can do it all in SOPC builder and use the Altera provided building blocks. This environment should allow you to create the whole system in a matter of hours.

If the microcontroller is an SPI master only, this might mean you're better off allowing the PCIe to talk to DPRAM and have the SPI slave controller in the FPGA talk to the other port of the DPRAM. If response times are important consider adding some GPIO pins to the PCIe side so the windows side can generate interrupts to the microcontroller. All this can be done quite easily in SOPC builder, but it isn't as simple as the other case.

If you have the pins available, don't forget to bring some of the GPIOs out so you can debug the progress of your windows driver code.