Simply unzip the BIOS file, boot to DOS, and flash the BIOS using AFLASH.EXE, which is either downloadable from the ASUS site, or you can get a copy of it on the CDROM included with your motherboard.
The ASUS P299-B should have no problems with Coppermines.....most PCB revs of this board have the voltage support necessary for Coppermines. Either way, it's safer to get an FC-PGA Coppermine and a slotket just in case your particular board revision does not support 1.65/1.70 volts.
Usually it's best to use the ASUS slotkets with ASUS boards.