Joe suggests:
[other useful stuff snipped]
> 3.  Plan. Plan. Plan!  Each location should either have their own
> Class C IP Space, or subnet an existing Class C.  If you plan on a
> net connection - get registered IPs.

Unfortunately this won't do you any good these days as both Sprint
and MCI will refuse to make routing table entries for stand alone
class C networks, so getting an "official" IP address ahead of time
is no longer useful (and may be impossible).

Expect that whenever you go to sign up with an ISP, and every
time you decide to change ISPs, that you will need
to change the IP Addresses that the world sees.  This either means
changing the IP address of every machine, or using a firewall that
hides the inside network IP Addresses from the outside world, so
that the only thing that has to change is the firewall (and DNS).

(At least until the world switches to IPv6, but I wouldn't hold my
breath.)

G.