I have two web servers at home and the are both for hosting pages
that are accessable to users on the internet and me at home. All you
do is get your domain and forward it to your IP. When you access the
domain at home it will just check the domain and forward to your web
server. Your computer would pick up that your web server is local and
access it that way. Then you would not need a intranet server to view
the web site at home.

Acceptable hardware for your web server:

My web server has a celeron 533MHz cpu in it (it is not the cpu speed
you really need) with 256MB of SD-RAM (this is what you need lots of)
20 GB IDE Hard disk, CD-ROM, Floppy, Standard motherboard and a 4MB
AGP Graphics card, no sound or other devices. It has to be plain, the
more devices that are in it the more resources are going to be taken
up.

If you had the server on a faster connection say at 1MB then you
would have a PIII equivilant and at least 512MB to maximise the
performace. The reason my server isn't that fancy is because it's on
a 56K dial up connection.

I have see quite a few Cobalt systems that run 200 sites on a
450Mhz AMD k6-2 and 256Meg of ram. So unless you are running
a lot of dynamic content proc speed does not matter much. As
far as ram, depends on the content you are serving. Lots of
the same file, ram will help. If every request is different
ram does not help as much.

As for separate servers, you can just use the access file
to send requests from the internal network to one doc root,
while external requests go to another. There is really good
doc for this on the apache web site.