Extracting Firmware or Bios

I don`t know where other place to ask so here`s the place.
I read in the news bout hardware hacking such as Bios and the Firmware hacking. And i'm curious just how exactly do we extract the firmware information ? I mean it`s ll embeded into a rom chip right so how the hell we extract it?

Extracting it wouldn't be a problem, just modifying it, if it's really read-only memory. Very few computers still use actual ROM, though. It's mostly flash memory now.
However, none of this is "hardware hacking".