(I hoped to get here before pytheas22, or anyone else, did, but here is some more details on how to install apache and other programs)
I just asked the same questions only 2 weeks ago, and I hope that I am of assistance.
To start off you need to have your own special IP address, you can check your by going to this website It will say BOLDLY what your IP address is, for you will need this later on. Now to install some programs that will allow you to host a folder on your computer.
Type the following in Terminal
Now to test that everything installed OK, go to firefox and in the address bar, type http://localhost/. You should get a page of some sort showing what files are in /var/www/. /var/www is where all of the files that you want to be available to others should be(you will need root when accessing and putting files into this directory).
sudo apt-get install apache2 php5 php5-cgi php5-cli php5-common php5-mysql
If you are going to use PHP in your web pages here is how to test it to make sure that it works. Just go to Terminal, and type the following
2. Insert the following line
sudo gedit /var/www/testphp.php
<?php phpinfo(); echo 'Hello World' ?>
3. Save and exit
4. test it in firefox: http://localhost/testphp.php
Hoping that you have some knowledge of html, you can write a homepage and save in /var/www/ , make sure that you save it as index.html, because that is the file that browsers look for when opening a folder(in this case /var/www/). Go back to firefox and test it by going back to http://localhost/ and seeing if it works.
Now here is the fun part, getting your page out into the web so that other people can access it. Remember you IP address, well here is where it comes into play. Go to dyndns.com and sign-up. Then click on services in the top toolbar, next click Dynamic DNS. Go through the process of registering a domain for your ip and allow it a couple of minutes to update. I really don't know how long it takes for them to refresh their database, so FILL ME IN HERE anyone who knows. Once it has entered your domain name, you can phone a friend and get then to go to the domain you chose during the registration. It ought to work. If not then ask your questions here.
A really hope that this helped.