Flashing over your BIOS can be risky and you should be aware of them BEFORE you attempt to do this especially if you're new at it. Another option is to have somebody who has more experience (a friend, relative?) help you out or let them do it if they are confident enough.
Anyways, if you want to do it.....do as BigNate said and go to your motherboard's manufacturer site and follow the links for the BIOS upgrades. It might even explain how-to there at the site but if not...do a search on "Flashing BIOS", "BIOS Flashing" or maybe something like that.
However, sometimes you have to depend on yourself to get things done, as I had to, and I flashed my BIOS for the first time and I followed their instructions and it worked!!
Try this link:
http://www.motherboards.org/articlesd.html?articleid=45&pagenum=2
Couldn't make it a hyperlink...no HTML code allowed in here, sorry. Just copy 'n paste in your browser and you'll be flashing in no time.
REMEMBER.....READ ABOUT THE RISKS!!
Good Luck,
Prayer Warrior