Softphone supporting TLS, SRTP and ZRTP as well as IPv6 and some HD codecs. Google Contacts can be imported.
.Net SDK for C# SIP WPF softphone development
Fax Voip Softphone 2.3.1
SIP/H.323 software telephone. Fax. Recording.
Internet phone to make calls using your PC
Ozeki.NET SDK to develop VoIP video softphone
.NET SDK to develop Silverlight SIP softphone