Here are a number of services available that allow you to make internet telephone calls utilizing VOIP for free. These services fall into two broad categories. 1) PC software applications made available for free or low-cost that enable PC to PC phone calls over VOIP and 2) VOIP service providers that allow free PC to PC phone calls as a lead-in to their paid services (such as PC to landline or mobile numbers). Many of these applications also enable IM or chat services between users, and some are compatible with Microsoft, Yahoo and AOL instant messaging.

The first category consists entirely of free or low-cost PC softphone applications that are widely available for download. These range from freeware to shareware to applications available for purchase. Most of these applications rely on existing PC hardware (microphone and speakers or headset) to implement a PC softphone. The common denominator for all of these applications is that both participants in the internet telephone call must be running the same PC softphone software, or at least running software that supports the same protocol on both ends.

A good example of programs such as this is ExpressTalk, which utilizes the SIP (Session Initiation Protocol) standard, one that has gained fairly wide acceptance. Microsoft Windows Messenger uses the SIP protocol. A SIP provider is required for ExpressTalk, but you can register with many SIP providers at no cost. ExpressTalk includes a rich feature set, with support for features such as CallerID, data compression, use of up to 4 lines and multi-party calling. ExpressTalk provides a very user-friendly interface with one-click access to the integrated phone book and one-click dialing. Currently, there is at least one SIP provider, Voipbuster, that is offering free calls to landline and mobile numbers. There is however, a 120-day limit to free calls before a fee is charged.

Another source for free PC softphones allowing free PC to PC VOIP calls is the major software download sites. Most of the applications available from these sites require both users to be running the same software. Also, many of these programs are freeware with limited support.

Probably the most recognizable name in the second category (free PC softphones offered as a lead-in to paid services) is Skype. This provider started a number of years ago by providing a PC softphone that enabled users to make PC to PC internet telephone calls for free. Skype has since evolved into a full-scale provider, but still offers one of the best free PC softphones available. Skype now offers SkypeOut and SkypeIn for calls to and from landline and mobile users. Although this is a paid feature, Skype has made this service available for free until December 31st, 2006. Also, there is a wide assortment of USB and wireless handsets and ATA- type devices available for use with Skype. Another advantage to using Skype is that it is available for PC, Mac or Linux platforms.

Other examples of this type of provider are Firefly and Gizmo Project. These providers offer a free PC softphone app that can be downloaded and used to make PC to PC internet phone calls for free. They also allow calls to landline and mobile users for an additional fee, which varies among providers.

Google Talk, which is still in beta form, offers a unique hybrid of features such as voice, chat, IM, email and file transfer. Google Talk will likely gain widespread use, and interoperability is a major goal for the product. Google Talk is currently available for free, and is free to use.

As you can see, it is still possible to obtain free VOIP service. While most of the free services allow only PC to PC calls to made for free, careful research can identify providers with lengthy free trials for calls to landline and mobile users.