Make completely free PC-to-phone and PC-to-PC calls.
iCall is a video and audio call utility that works on Windows and Macs, as well as most mobile devices. iCall supports free calling (including conference calls up of to 10 people) anywhere in the U.S. and Canada, or international calls for a fee. There are also some pay-as-you-go capabilities so you can select the options that suit your needs, or there's an "everything" package called iCall Total Access. iCall can also assign you a free phone number to allow others to call you. The software downloads and installs easily, but you need to set up an account to use iCall.
Improve quality of your Web phone calls.
Make cheap international calls worldwide.
Manage phone calls in a business or call center environment with virtual IP PBX software.