The whole idea of NVMe is that it will be natively supported by the operating system, and shouldn't require additional drivers. That doesn't mean that Intel for example won't release optimised drivers for their chipsets.
Consumer NVMe will probably be restricted to 8 PCIe3 lanes, to allow the addition of a graphics card. The current crop of consumer grade NVMe drives will probably be 4X PCIe3. allowing transfer speeds of up to 40Gbps (4GB/s) transfer speeds. Enterprise class NVMe drives could probably use 16X PCIe3 or in other words, up to 160Gbps (16GB/s) transfer speeds.
Probably more important than the transfer speeds is, latency will be much lower, and support for queue depths beyond 65,000.
I would guess the first consumer grade NVMe SSDs will use a 2.5 inch form factor and look much like a SATA 2.5 inch drive, except instead of a SATA connector at one end of the drive, you'll find a PCB edge connector much like a graphics card, which can be plugged into a standard PCIe3 16X socket.
Future motherboard chipsets, such as the Intel Z170 chipset for the SkyLake platform due H2 2015, may have PCIe3 4X sockets designed specifically for NVMe SSDs.