Updating Firmware?

[Brian Fish]

Hi all,
 This may sound trivial,but...how do you update firmware?  I've heard it
said, many times, many ways.  But where do you find the latest firmware?
Would it show up in Software Update or am I suppossed to go to some section
of Apple's site?  Also, how do you know when firmware updates are available?
Every other 'ware'  is pretty self explanitory, but firmware is one that
kind of went over my head.  Thanks for any help.

-Brian