XO Hosted PBX - Hosted PBX is a scalable UC solution that uses cloud technology to integrate HD voice & data services, mobility, along with advanced calling

Linphone - Linphone is an internet phone or Voice Over IP phone (VoIP).

Zoiper - Cross-platform VoIP softphone dialer for SIP and IAX systems

Sipdroid - Free and open-source SIP/VoIP Client

Ekiga - Ekiga (formely known as GnomeMeeting) is an open source VoIP and video conferencing application for...

Nani? - Offline Japanese dictionary for Android.