If you do not like Skype, you may find competitive products for free instant VOIP communication.
Ekiga, formerly GnomeMeeting, is a free, open source, multi-platform softphone, instant messaging, and video conferencing application, supporting some of the most popular internet telephony protocols (SIP and H.23).
* Ease of use with a modern GUI (Graphical User Interface).
* Audio and Video free calls through the internet.
* Free Instant Messaging through the internet with Presence support.
* Audio (and video) calls to landlines and cell phones with support to the cheapest service providers.
* High Definition Sound (wideband) and Video Quality up to DVD quality (high framerate, state of the art quality codec and frame size).
* Free of choice of the service provider.
* SMS to cell phones if the service provider supports it (like the default provider).
* Standard Telephony features support like Call Hold, Call Transfer, Call Forwarding, DTMF.
* Remote and Local Address Book support: Remote Address Book support with authentication using the standard LDAP technology, Local Address support in Gnome (Evolution).
* Multi platform: Windows and GNU/Linux
* Wide interoperability: Ekiga use the main deployed stantards for telephony protocols (SIP and H.323) and has been tested with a wide range of softphones, hardphones, PBX and service providers.
Developer’s website: http://ekiga.org/
Portable version (from PortableApps): http://portableapps.com/news/2013-10-30--ekiga-portable-4.0.1-released
Jitsi, formerly known as SIP Communicator, is a free and open source program for instant messaging and VoIP. Primarily written in Java, Jitsi supports multiple operating systems and a wide variety of internet telephony and chat protocols such as SIP, XMPP and YMSG. Jitsi allows audio and video calls, instant messaging, desktop streaming, and sharing, call hold, call recording, and encryption for calls and chats (OTR).
Jitsi has placed the service security as one of the main necessary functions for the product development. It is characterized by the following features:
* Encrypted password storage.
* Password protection with a master password.
* Encrypted Instant Messaging with Off-the-Record Messaging (OTRv4).
* Chat authentication with the Socialist Millionaire Protocol over OTR.
* Call encryption with SRTP and ZRTP for XMPP and SIP.
* Call encryption with SRTP and SDES for XMPP and SIP.
* DNSSEC support.
* TLS support and certificate-based client authentication for SIP and XMPP.
Developers’ site: https://jitsi.org/
Instructions on how to install and start using: https://jitsi.org/Documentation/InstallAndSetupOnWindows
Portable version (from Sourceforge): http://sourceforge.net/projects/jitsiportable/
MicroSIP is a portable, open source softphone appfor making calls using the SIP protocol. It allowing to do high quality VoIP calls (person-to-person or on regular telephones) via open SIP protocol. From cloud of SIP providers you can choose best for you, register account and use it with MicroSIP. You'll get free person-to-person calls and cheap international calls.
* Small footprint (>2.5MB) and RAM usage (>5MB) - written in C and C++ with minimal possible system resources usage.
* Usability - user friendly in daily usage.
* Functionality - voice; video H.264 and H.263+; SIMPLE messaging (RFC 3428) and presence (RFC 3903, 6665).
* Compatibility - strongly conform to SIP standards.
* Voice quality - supports best voice codecs: speex@8,16,32kHz, iLBC@8kHz, GSM@8kHz, G.711@8kHz (PCMU and PCMA), G.722@16kHz, G.729@8kHz, SILK@8,12,16,24kHz, Linear PCM@8,16,44kHz.
* Privacy - configurable encryption TLS / SRTP for control and media.
* Portability - stores setting in ini file.
* Multilanguage interface - included localization files for Brazilian, Bulgarian, Chinese, Dutch, Estonian, Finnish, French, German, Hebrew, Hungarian, Italian, Korean, Norwegian, Polish, Russian, Spanish, Swedish, Ukrainian, etc.
Developers’ website: http://www.microsip.org/
Download (pick between installer version or portable, which is always recommended): http://www.microsip.org/downloads