Moved to Fireworks forum.
Thanks, sorry about that I was clicking through support and this is where it sent me
If there were a simple way to do this, I think you'd find it within Preferences. It may not be possible.
Fireworks is really all about the pixels, and doesn't have the "print" orientation that Photoshop does (where output is routinely measured in inches).
I was going to suggest using View > Grid > Edit Grid… to set up a custom grid that could approximate inches. For example, if your resolution were at 72ppi, you could set the grid unit to 72px. But this would be an abstract version of inches, much smaller than the actual units. If you knew the resolution of your monitor (e.g. 106ppi), you could set up a good approximation of inches; however, Fireworks seems to have an upper limit of 100 pixels as the grid unit, so you'd need to at least divide your resolution in half (e.g. 53px) to draw a grid line every half inch.