MicroSIP is Free VOIP (Voice Over IP) software that enables you to make secure, high-quality phone or video calls over the Internet. It supports direct point to point communication by IP address — ideal for connecting with other Micro SIP users at no cost. Alternatively, it can be used with a paid SIP service provider to call regular landlines and mobile numbers.
Loudtalks Lite is a Free Portable Tool that supports Push to Talk (PTT) Voice Over IP (VOIP) communication. It functions similar to popular software like Skype. However, with it's distinct advantages, some consider Loudtalks a Skype Replacement. Real Time, Face to Face like voice communication. It's Unobtrusive, you can listen when you want. You can receive messages if you are not at your PC and listen to them later on. You can have multiple independent conversations simultaneously. You can also have live group voice conversations with a few to hundreds of people at once. There are versions for Windows Mobile and Windows devices (So you can also run it from your phone).
PicoPhone is a Free VOIP Internet Phone application with built-in text chat capabilities. Designed with simplicity and efficiency in mind, it was developed as an alternative to the many VOIP solutions that rely on overly complex protocols, which often struggle behind NAT or NAPT routers. Instead, it uses a straightforward, UDP-based protocol that is lightweight and highly compatible with network address translation setups. This makes it an ideal choice for users who need a reliable and hassle-free Internet phone solution.
12Voip is free Portable Voice Over IP software (Internet Phone). Like many other VOIP products, it enables a computer user with internet access to have superb high quality voice conversations with friends and relatives from all over the world. Using this tool, you can call landlines or even mobile cell phones for free * in the USA and many other Countries, using only a computer and an internet connection. You can also call online friends using peer-to-peer calls.
Making Skype Portable: Skype remains one of the most well-known and widely used VOIP (Voice Over IP) telephony clients. With Skype, users can make voice and video calls, send messages, and share files—all over the Internet. In this tutorial, you'll learn how to run Skype directly from a USB flash drive, so you can carry it with you and use it wherever you go.