IP xStream
IP Telephony data source.
http://www.iptelephony.org

Iscom, Inc. PCCall Service
PC to Phone call services.
http://www.iscom.net

1888usa.com
Lists free fax and phone resources on the web.
http://www.1888usa.com

RADVision
SIP, 3G-324M, H.323 stacks and testing tools for VoIP vendors.
http://www.radvision.com/

Inter-Fone - VoIP Internet Telephony
Internet-carried Phone to Phone calls.
http://www.inter-fone.com/

iBasis
Provider of wholesale international IP telephony services.
http://www.ibasis.net

InternetTelephony.com
Industry newsletter for telecom professionals.
http://industryclick.com/magazine.asp?magazineid=7&siteid=3

CentraNow
Web meetings powered by Voice over IP.
http://www.centranow.com

Internet Telephony: America Is Waiting
FCC Chairman Kennard's remarks before the Voice Over Net Conference; Atlanta, Georgia; September 12, 2000.
http://www.fcc.gov/Speeches/Kennard/2000/spwek019.html

TEK DigiTel Corporation
Provides communications solutions for the small to medium size business by integrating traditional PBX technology with data routing and VoIP technology.
http://www.tekdigitel.com/

Voice Systems Research, Inc.
Provides unified messaging, voice mail, advanced call routing, and IP-based telephony solutions.
http://www.vsrusa.com/

SecureLogix Corporation
Provides enterprise telephony management systems.
http://www.securelogix.com

VoIP.org.uk
UK resource with the emphasis on small businesses and home users. Includes news, reviews, and forums.
http://www.voip.org.uk/

VOIP EZ
Offers in depth information on implementing VoIP in both consumer and commercial settings.
http://voipez.com/

Wikipedia: Voice over IP
Encyclopedia article with background information, technical details, and the advantages and disadvantages of VoIP.
http://en.wikipedia.org/wiki/Voice_over_IP

VoIP Wiki
A wiki that covers VoIP software, hardware, service providers, reviews, configurations, and standards.
http://www.voip-info.org/wiki/

VoIP Watch
A weblog with news and reviews of VoIP products.
http://andyabramson.blogs.com/

Voice over Internet Protocol
An overview of VoIP from the Federal Communications Commission. With news, FAQs, factsheets, and findings.
http://www.fcc.gov/voip/

Packetizer
Technical information about VoIP and videoconferencing.
http://www.packetizer.com/

Voice over IP and IP Telephony References
A directory of talks, papers, books, organizations, vendors, standards, web pages, and standards on IP telephony.
http://www.cs.wustl.edu/~jain/refs/ref_voip.htm

IP Telephony Literature Survey
A literature survey covering architectural, protocol, and quality requirements for deploying an IP Telephony service.
http://www.cs.berkeley.edu/~mccaesar/research/iptel_litsurv.html