simple apache2 setup

What Im trying to do I know is fairly simple yet one of those things you dont do too often so you tend to forget the little details (not to mention changes to the software that certainly have happened)...

REAL basic...REAL simple: I'm trying to get apache2 running a web page. I'm running debian.
Ive done this before and the old one is running. Everything is in place here at work. I just want to get this one going and swap in the newer PC/installation.

-Dont care about cgi or perl or ssl, etc, just a basic web page.
-I want to drop my web files in to /var/www and be up and running.
-The older PC is currently running with apache2 (installed a when apache2 was new), on an older machine, older version of debian.

After the fresh debian w/apache2 install on the newer PC, I type "localhost" and got "It works!" message in the browser. :)

I drop the web files into /var/www and type localhost and I -do- get the web page. :)

I go to another PC and type the address but it cant be found, even though its static IP has been plugged in. (the web page is working now but only because I put back the older PC :(

From other "outside" connections, it cant be seen. Should be working just like the older one that's up and running now.

What simple, yet important edits have I forgotten or need to recheck?
I'm sure it would take no more than 3 minutes to get it running if I could remember what to edit/do.

Has anyone recently set up apache2 and can help - what, if any, configuration files did you have to edit?

TIA

David