ISPhone Inc.  
   Wholesale voice over internet services.
   http://www.isphone.net/

PC2call  
   PC-phone internet voice service provider based in the United Kingdom.
   http://www.pc2call.com/

Mywebcalls  
   PC-Phone or device-to-phone United Kingdom based service.
   http://www.mywebcalls.com/

Vonage  
   Provides voice over internet local dial-tone service. No PC required. Uses analog telephone with broadband telephone adapter.
   http://vonage.com/

Skype  
   Peer to peer internet voice service. Requires PC for both callers.
   http://skype.com

Packet8  
   Voice over internet direct dial service without a PC. Owned by 8X8, Inc.
   http://packet8.net

Free World Dialup  
   Community network allowing calls to toll free numbers in the US, Japan, UK and Netherlands. Peer-peer calling to other members.
   http://www.freeworldialup.com/

SIPphone Inc.  
   Peer-peer calling service. Requires SIP adaptor and phone.
   http://sipphone.com

Asterisk  
   An open source telephony switching and private branch exchange service. Allows peer-peer calling using a variety of voice over internet protocols.
   http://asterisk.org

Callserve  
   PC-to-Phone service for outbound calls only. Software download required.
   http://www.callserve.com

Dialpad Communications, Inc.  
   Offers monthly billing and pre-paid PC-to-Phone VoIP services. Also supports broadband telephone adapter for use without PC.
   http://www.dialpad.com

MeaPhone  
   PC to phone service based in Thailand. Software download required.
   http://www.meaphone.com

Dow Networks  
   Provides Voice over IP and telecom service to international clients.
   http://www.downetworks.com

Calleveryone.com  
   A full featured VoIP/broadband phone to phone service primarily for calls within the US.
   http://www.calleveryone.com

RhinoBell  
   PC to phone, phone to phone using device, voice over internet calls.
   http://www.rhinobell.com/

Talafone  
   Canadian based provider of PC-to-phone and IP phone services and hardware.
   http://www.talafone.com

VoipXchange  
   B2B VoIP exchange platform for carriers to buy/sell excess capacity on VoIP networks covering call termination in 250+ countries. No-fee membership required.
   http://www.voipxchange.net

iConnectHere  
   Offers VoIP-based PC-to-Phone, Broadband Phone and Calling Card services.
   http://www.iconnecthere.com/

Vodawave  
   Residential and enterprise VoIP plans plus gateways, gatekeeper and billing software.
   http://www.vodawave.com

Efonica  
   Prepaid system for PC-to-phone and web initiated phone-to-phone using VoIP.
   http://www.efonica.com

Dial2Home  
   VoIP service for phone-to-phone with adapter or peer-to-peer.
   http://www.dial2home.net/

VoicePulse  
   VoIP service offering phone-to-phone with device. Various features and calling plans.
   http://www.voicepulse.com/

Vinculum Communications  
   VoIP wholesale international termination services provider.
   http://www.vincomm.net

VoIPOnline  
   Voice-over-IP news, supplier directory and chatrooms for discussing related industry topics.
   http://www.voiponline.com

One Unified Net  
   A communications infrastructure provider includes IP systems, services, softswitches, and phones.
   http://www.oneunified.net

VoIP Providers List  
   Information exchange for VoIP partners offering minutes termination and origination, as well as hardware and software trade.
   http://www.voipproviderslist.com

Voice over IP Calculator  
   Free VoIP resources, including online bandwidth calculators, white papers, books, a directory and a forum.
   http://www.voip-calculator.com/

Super Technologies, Inc  
   Offers flat-rate unlimited calling within USA & Canada. Uses analog telephone handsets via broadband telephone adapter.
   http://www.virtualphoneline.com

BroadVoice  
   VoIP provider offers full feature set with voice mail, caller ID, etc. Requires supplied broadband phone adapter.
   http://www.broadvoice.com/

Redshift Networks  
   Operates and builds international carrier networks using VoIP and TDM circuit transmission technologies.
   http://www.redshiftcorp.com

IPCB.net  
   Softswitch services such as routing, billing as well as VoIP call termination.
   http://www.ipcb.net

Voiceglo  
   VoIP service offering free and paid plans. Some plans require phone adapter or USB phone with an Internet-connected computer.
   http://www.voiceglo.com

VocalNet  
   VoIP provider offering residential and business plans.
   http://www.vocal-net.net/

Asylum Telecom  
   VoIP provider for business and residential customers. No service charges.
   http://www.asylumtel.com

v59  
   Use dial-up and talk everywhere with our VoIP service
   http://www.v59.net

CallDaddy  
   Pre-paid VOIP services. H.323 IP phone, gateway, gatekeeper, NetMeeting or any other H.323 compliant terminal necessary.
   http://www.calldaddy.com

On Instant  
   PC-to-PC only isntant messaging service with VoIP features including live voice, voicemail and CRM tools.
   http://www.on-instant.com

WhistlerTel Inc.  
   US provider of broadband internet phone service and voice over IP (VoIP) solutions.
   http://www.whistlertel.com