Source: snapvoip.blogspot.com

Essentials of Successful VoIP Migration
December 6, 2007, 1:00 p.m. Eastern Time
Targeted at Technology decision makers in small and medium-sized organizations, Cisco is presenting another of it’s Seminar and webcast series programs.

Agenda
VoIP Fundamentals
# Clearing Up the Terminology
# QoS, codecs, VLANs
# Myth Hackers - Will a Worm Trash My System?

VoIP Call Control
# Vision for Cisco Unified Communications
# Private Branch Exchange (PBX) vs. VoIP - Mapping the Functional Differences
# Protocol Choices
# Third-party Value: SolarWinds and the Orion Framework

Security Concerns
# Control File Protection
# Voice Encryption
# Myth Hackers: Eavesdropping
# Best Practices

Beyond the Dial Tone
# LiteScape’s OnCast for WebEx Integration
# Five Keys to a Successful VoIP Deployment

If you are interested, please visit Video Broadcasts site at Cisco and select Essentials of Successful VoIP Migration.

Source: snapvoip.blogspot.com

FCC, Federal Communications Commission, states that "Voice over Internet Protocol (VoIP), is a technology that allows you to make voice calls using a broadband Internet connection instead of a regular (or analog) phone line. Some VoIP services may only allow you to call other people using the same service, but others may allow you to call anyone who has a telephone number - including local, long distance, mobile, and international numbers. Also, while some VoIP services only work over your computer or a special VoIP phone, other services allow you to use a traditional phone connected to a VoIP adapter."
Let’s see how others describe it.
Howstuffworks tries to give you much information as possible with the article "How VoIP Works". I have gone through the complete article and found it to be ok. My writing ability is not as good as Robert Valdesz (It is getting there), otherwise I would try to write a simpler version as well.
He starts with how VoIP Works, How current PSTN, Public Switched Telephone Network, works which continues to the bits and bytes involved in a regular Telephone call, Advantages of VoIP, Disadvantages of VoIP and Codecs, softswitches and protocols.

All in all you get an idea of How VoIP Works but I wonder if the article ib being kept updated, for instance about E911, A lot has changed since it was written. So that is "How VoIP Works" until my writing improves. If I find any other VoIP introductions, I will Post them here.