From: www.quickstartvoip.com
Free Internet phone service lets you to make free long distance calls over the Internet in three different flavors. The first enables you to make calls from one phone to another as long as both are connected to broadband lines. The second allows you to make calls from one computer to another and the third makes calls possible from a computer to a traditional phone.
But, there are limitations to free services. Let’s take a look.
Phone-to-phone service providers require that you purchase their telephone adaptor (or ATA). As long as you are calling other people who have purchased the same equipment, the call is free. PhoneGnome is one such service. The PhoneGnome adaptor costs about $119. You literally plug it in to your broadband connection and to your regular phone, it configures itself, and you are good to go. You can start calling other PhoneGnome users anywhere for free. You don’t have to switch phone numbers or change telephone companies. Vonage, Packet8, AT&T CallVantage, and others you may have heard of follow the same model.
PC-to-PC service providers allow users to make free calls from one PC to another. Both parties need a PC with an Internet connection and some software easily downloaded from the Net. However, for a call to ring through, both parties have to be online at the same time and have the same, or at least compatible, software. By adding voicemail to a PC-to-PC service though, callers can leave messages even when you’re not online. Unfortunately, voicemail may or may not be free.  Skype, Gizmo Project, and FWD are three typical PC-to-PC services.
PC-to-phone services let you to call a regular phone numbers for free. However, you may be restricted to the locations that you can call or the length of the call. VoipBuster, for example, provides free calls from your PC to landline phones in about 30 countries. The restrictions are a little bit complex, but free is free…Lucky for us, the bigger software-based phone companies are trying hard to entice users so there’s also a current wave of promotions trumpeting free calls to landline phones. Skype for example offers free calls to any phone within North America until the end of the year. Gizmo offers free calls to phones in 60 countries as long as both parties maintain an active Gizmo Project account.
In all of these cases, free Internet telephone services make money by selling credits for calling minutes to landline phones or mobiles, long distance destinations, or phone numbers not on the same VOIP service. Rates are low, however, and you can expect to save significantly over traditional long distance companies. For regular phone users to call you on your free Internet phone account, you must “buy” or subscribe to a conventional phone number. Most services allow you to buy a phone number in different locations, so if your family is in the UK and wants to phone you regularly, you can buy a local UK number that they can call for free or inexpensively.
