> So I have been reading about m0n0wall but so far I have not been successful in finding what kind
of hardware set up I will require. 

Anything that FreeBSD 4.10 will run on. I personally have it setup on
Dell Optiplex GX150 933mhz mini-towers, and even an HP Brio celeron
500 at home. There is a hardware page in the documentation section.

The NIC's I use are D-Link

While you can run from HD or Cdrom + Floppy from a worstation class
computer, I have my routers using compact flash cards with a CF-to-IDE
adapter

Minimum memory is 64mg ram, but do yourself a favor and use atleast
128mg for future upgrade paths.

>My home setup is: cable modem -> router -> VOIP device. Where do I
insert the m0n0wall computer?

M0n0wall could take the place of your existing router.

> VOIP

There are lots of threads on this subject. Do a google search using

voip site:m0n0.ch

where voip is the keyword and "site:m0n0.ch" limits the search to this
domain. I suppose you could also use other search words as well.

- Don