1)   3CX VOIP Phone for Windows 6.0
Free VOIP / SIP phone (softphone). Use your PC as a phone. Works with any SIP / VOIP provider and phone service. Easy to use interface to transfer, forward calls or review history of calls. Free download from http://www.3cx.com

 2)   Globe7 8.0.0.1
Globe7 is a tiny application integrated with Soft Phone, IM, Videos, Games, News and many more opt-in widgets like Live TV, Live Radio, Astrology, Forex, Movies, Pets, Recipes, Sports for your complete entertainment, information and communication.

 3)   Express Talk VoIP Softphone 2.06
Express Talk is software that works like a telephone to let you make calls from your PC. With Express Talk you can call anyone on the internet who has installed Express Talk (or any other SIP voip softphone). Calls are free.

 4)   ZOIPER Free SIP and IAX softphone 2.14
ZOIPER 2.0 Free Edition is a user-friendly IAX and SIP softphone compatible with the Asterisk platform or any other IAX or SIP capable system. ZOIPER Free . Find out the many advantages of this FREE product from Attractel!

 5)   FREE PHONE 2.0.0.0
FREE Phone is a free downloadable soft phone which enables you to make calls from pc to pc, pc to mobile and pc to landline. FREE Phone offers you a free phone number to make free pc to pc calls and receive unlimited free incoming calls from any phone.