I am interested in offering free e-mail service to an unlimited amount of users. The service will be similar to Yahoo Mail or Hotmail. I have done some research and come accross terms like Web/Domain Hosting, Mail Server, iMail. Some companies also offer licenses for anti-virus, anti-spam and a specific number of users. I've also discovered that there are certain programs that provide e-mail portals that are customizable and some portals that are not customizable.

My question is, please explain as simply as possible, what are the steps I will need to take to establish free e-mail service to an unlimited amount of users similar to the big name e-mail providers?

Please also define the various terms that I am likely to face. Thank you.

All I can say is good luck, because you'll need it. There are already a good amount of e-mail providers that are free and have a great amount of space for the consumer to use, so you are definately not without stiff competition.

You will need to have the hardware to do this and the cheapest way is a dedicated server that uses WHM. You would also need an automated form that not only allows your visitors to create an account but that also automatically sets up these mail accounts on the server. I have not done any search but you should be able to find a server side application that does this for you.