Skype

Peer to peer internet voice service. Mac, Windows and Linux versions available. Users may call landlines and cellphones for a fee; users may call each other for free.
http://skype.com

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/

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/

Efonica

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

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

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/

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

OneAccess Networks

Broadband access solutions including IP routers, voice over IP (VoIP) and voice over DSL (VoDSL) solutions, concentrators and networks adapters.
http://www.oneaccess-net.com/

PingTone

Business VoIP provider geared toward companies deploying Cisco Systems IP Phones.
http://www.pingtone.com/

Onramp Access

Provides business oriented VoIP services across fully managed T1 connections.
http://www.onr.com/voip/

Snaptel Communications

Offers pre-paid PC-to-Phone VoIP services worldwide. Uses Netmeeting.
http://www.snaptel.net

SCS Telecom GmbH

German-based B2B VOIP provider offers services to local call-shop owners and calling card telcos.
http://www.scs-telecom.com/

Calltower, Inc.

US-based B2B VoIP provider offers enterprise class hosted VOIP PBX Systems.
http://www.calltower.com

WERCS Communications

US-based B2B VoIP telephony provider offering converged ip voice and data network services to customers in Wyoming and Rocky Mountain region.
http://www.wercscomm.com

World On IP

Italy-based B2B VoIP provider offering hardware to set-up wireless VoIP networks.
http://www.worldonip.com/voipwirelessphone.htm

My VoIP Store

Australian-based (Brisbane) VoIP consultant and B2C e-commerce site for VoIP hardware.
http://www.myvoipstore.com.au

Texas Instruments VoIP Solutions

B2B manufacturer of VoIP equipment including IP Phones, VoIP Gateways, High Density Gateways, voice-enabled Cable & DSL Modems.
http://focus.ti.com/general/docs/bcg/bcggencontent.tsp?templateId=6116&navigationId=11903&path=templatedata/cm/general/data/bcgovrvw/voip_solutions

Voxilla

News, forums, reviews and guides for IP telephony devices and services.
http://www.voxilla.com

Click4netphone

Pre-paid Internet Telephony Services via VOIP.
http://www.click4netphone.com