I have an Intel PM55 chipset in my notebook. Reportedly Windows 8 (aka Windows Next) will not support BIOS-based systems. Is my motherboard forward-compatible to house an EFI firmware?
The Intel PM55 is available with the recent Core I5 & I7 chip families and is 64-bit.
As such, while your current system probably still only supports booting the BIOS-based OS via the Compatibility Support Module (CSM), and thus does not appear to be UEFI-based, actually it's almost certain to be UEFI-ready for Windows 8 which will be only UEFI-based and 64-bits.
However, you will need an EFI update package for your motherboard, which given the great popularity of the Intel PM55 chipset, has a good chance of eventually becoming available.
But nothing is ever guaranteed, as there is not enough documentation available at the moment.
Until MS decides to discontinue the 32-bit version of Windows, it'll continue to support BIOS. Even then BIOS support is highly unlikely to be removed, because most UEFI implementations have CSM module for legacy support and many people still rely on that.
UEFI is newer than BIOS and has a lot more features. It contains a lot of modules, including CSM module for emulating the old BIOS. As a result it's much larger and can't be stored in a BIOS chip. Therefore BIOS systems generally cannot be upgraded to UEFI
However if really needed then a software UEFI solution like DUET can be used
If your computer is based on a true BIOS, though, how can you make it act like a UEFI-based system? The answer is to use a disk-loaded UEFI implementation known as the Developer's UEFI Environment (DUET; or sometimes UEFI DUET). This software is a real, although limited, UEFI implementation that can be booted like an OS from a computer's hard disk. Once it's in control, DUET provides typical UEFI services to UEFI-based boot loaders and OSes.
More information: What can TianoCore's DUET be used for in a PC?
Even nowadays many PCs are shipped without CSM module. Intel has announced the plan to remove BIOS support completely in the future
Speaking at UEFI Plugfest, a hardware interoperability testing event held by the Unified Extensible Firmware Interface (UEFI) Forum earlier this month, Intel announced that by 2020 it was going to phase out the last remaining relics of the PC BIOS by 2020, marking the full transition to UEFI firmware.