Okay, first a couple issues I want to bring to your attention before you proceed:
1. Are you ready to manage a server with 24/7 uptime?
2. I hope this isn't your personal computer, because once you start serving, thats pretty much all that computer will be used for, no playing Diablo2 or Quake while serving.
3. You mention cable modem connection. Have you checked with your cable company and/or their terms of service to see if they allow people having servers on the service? Pretty much every cable modem provider I know of forbids residential plan users from having a server running on the service. You may have to purchase the business plan which some cable providers now offer.
4. You will also have to get a static IP address. Most DSL and cable modem providers don't come standard with static IP's, but most have an extra purchase option for it.
Well now, if you're fine on the above, you are going to have to do some reading:
1.
http://www.apache.org for the server software and literature
2.
http://www.perl.com for perl and its related literature.
