Voice over IP: what it is, why people want it, and where it is going
by Jane Dudman, Contributing author: Gaynor Backhouse
Article published by JISC Technology and Standards Watch, September 2006 (PDF)

VoIP How to
VoIP systems and standards
http://www.tldp.org/HOWTO/VoIP-HOWTO.html

VoIP Services - Voice over IP Providers - VoIP Termination
iCallGlobe Ltd. - Offers lucrative international VoIP termination rates for the carriers and other VoIP service providers. iCallGlobe provides quality termination to various European, Asian and African destinations through their various telecom partners.
http://www.iCallGlobe.com

VoIP News
Enterprise, Carrier, Small Business VoIP Information
http://www.voip-news.com

VoIP Providers - VoIP Services
VoIP Review is committed to bring to you the best broadband phone company providers. To find the best broadband phone company providers use our search tool to search.
http://www.voipreview.org 

VoIP Services
VoIP News and reviews
http://www.voipres.com

eg3.com
eg3.com is a leading portal for embedded systems, RTOS, DSP, boards and more.
http://www.eg3.com

VOIP National: VOIP Providers & Services
Search and compare from among several leading VOIP service providers and VOIP equipment products.
http://www.voipnational.com

VoIP Provider - VoIP Solution - Broadband Phone Company Service
Dedicated to Voice over IP & Broadband Phone service.  Use our FREE and personalized VoIP provider plan search engine and VoIP reviews to compare a vast number of internet phone service plans.  Choose a VoIP solution that meets your particular telephony needs.
http://www.whichvoip.com

VoIP Basics
An introduction and guide to voice over IP and free telephone calls.
http://www.voipbasics.co.uk/introduction.jsp

VoIP Providers
Reviews of top VoIP providers. Choose a provider based on features, price and rating.
http://www.voip-review.org

VoIP 101
Online guide to selecting VoIP Internet phone service and equipment.
http://www.voip-101.com

VoIP Service
VoIP-Solution.ca is the official authorized seller of the VoIP Phone Service and VoIP Adapter for the US and Canada. Use your current broadband or dialup connection to make unlimited residential long distance VoIP phone calls 24/7. Only 16.97 a month.
http://www.voip-solution.ca

VoiceGate - Call Monitoring/Call Logging
VoiceGate.com - An innovative leader in the call monitoring, voice recording, call logging industry.
http://www.voicegate.com

VoIP App
Your Online Guide to VoIP
http://www.VoIPApp.com

Fore Voip
Your premier Voip resource on the Web!
http://www.forevoip.com/articlevoip

Voip providers at Voip Resources
Voip providers Information and Resources Online
http://voip.voip-resources.com

VoIP Service Providers Resource
VoIP resource for articles, reviews and advice on Internet telephony-related hardware, software and service providers.
http://www.voipresource.net

Voip Directory
Voip Service Providers list, over 100 Companies.
www.voip-brands.com

MERA VoIP Products and Solutions
MERA Systems is the forefront provider of session controllers for real-time reliable and secure VoIP peering
http://www.mera-systems.com

Intevox.com
IP telephony news and information for the Research Triangle Park.
http://www.intevox.com

ISI Telemanagement Solutions
Call Accounting and Telemanagement solutions
http://www.isi-info.com

Best Discount Long Distance Rates
Discount long distance and Internet services. Cheap International calls, Free cell phones, Dedicated T1 and More...
http://www.goldcoastphone.com

Conference Calling Service
Phone conferencing and web conference services. Do you want pay
by the minute toll free conference calling service or flat rate conferencing?
Best Conference Calling has both - with NO hidden fees. International
access numbers available with all plans.
http://bestconferencecalling.com

IN-Call.com
VoIP PC to Phone, PC to PC, and Phone to PC Telephony Service Provider. Cheap Internet Phone Calls anywhere, even international
http://www.in-call.com

Free Directory of PC to Phone Providers
PC to Phone and PC to PC & SIP VoIP Information. Use PC to Phone VoIP to make cheap Long-Distance calls using your computer.
http://www.netphonedirectory.com/