how do i update my bios

I have a BFG 680i mobo. tomorrow i am going to flash the bios. what do i need to do to update it?
i have heard that there is a special button that you press during POST (ie f2) but i dont know which one will work for my mobo.
this is a first so any info is welcome.

ps if anyone can tell me which is better a usb stick or floppy?

I have a manual version 1.0 for my BFG 680iUltra. There is no mention of a procedure to update the BIOS. I'm also looking for the procedure to update the BIOS.
I also would like to know if the latest BIOS will work with a Conroe. I ask because I like to do things one at a time. Example: I'd like to use my existing E6550 CPU to update to the latest BIOS. If the flash goes smoothly, THEN, I'll buy an E8500 and swap my CPU's.
That's my theory, anyway.
One more thing, I see forums that the latest BIOS version is "P32". Where are you getting that number? I don't see anything like it in nVidia Control Panel, nor do I see anything like it in Sisoft Sandra.
From what I can see in "Manage Your System BIOS,
my BIOS version is 2.053.82
dated 5/15/2007
BIOS ID 6A61IL03.

Thanks. I've heard some horror stories about flashing using ntune, but you are proof that it works. Today, I got a response from a BFG tech through an email saying "burn the update (which is in ISO format) onto a cd and set your "first boot" sequence to cd. I haven't tried it but I'm glad to have a couple of options. To anyone else reading this, the BFG tech also said that the P04 update will work with my Conroe (E6550) CPU so I can update first, THEN upgrade to a Wolfdale at a later date.

Thanks again for the info.