Umm, BIOS updating could be a nasty thing. Well.
There are several solutions:
a) You have an ASUS board. They offer the so called "EZ flash" feature (I think I saw something similar on... was it Gigabyte?) - there you just put the BIOS image file on anything FAT formatted (USB stick, CF-Card, even a partition on your HDD, good old floppy e.g.) and tell the in-Bios-update-program where to look for the imagefile. Then it'll read the file in, display version info and ask you if you want to update. Say yes and there you go. 1 reboot and it's all done.
I consider that a very decent feature of my ASUS boards, makes BIOS updating system independent and very comfortable.
b) You have no such EZflash or similar stuff. Well, a lot of older boards just uses the good old "make a bootable (free)DOS floppy" method. You just create a DOS floppy and put the image file there. They'll provide you with some AMIflash, Awardflash or something DOS-executable which you call often by awdflxxx (xxx ist often version) some parameters and at last the BIOS image file you want to write into your BIOS.
The good thing is that by means of FreeDOS everybody is able to create such a floppy, no need to pay MS.
Often Mainboard vendors even offer these kind of bootdisk images and often they already contain the very FreeDOS plus an automated setup by autoexec.bat containing the neccessary steps.
b2) in case the provide you only that exe file for BIOS, check it! It's often nothing but a self-extraction version, rar/unrar, zip or something.
Either you try it in WINE (don't try to flash the BIOS from withing WINE or DOS emulators, it prolly won't work) - so it will extract itself or use some tool (unrar, p7zip etc.) to try to extract the image file and then use the procedure described above (maybe you have to get some AWDflash or something still).
c) they only provide you with a Windows-only-updater? Kick that vendor from your buy list. And tell them that they suck.
For updating BIOSes within Linux, there should be a few methods, but I didn't try them. Afair Dell supports a Linux based update prog and I dunno if you can activate some stuff in your Kernel to read and write EEPROMs. Thus you should be able to access any EEPROM in your box and write whatever you want to it. I think it's possible but that would maybe something for Michael to make an article.
Stop TCPA, stupid software patents and corrupt politicians!