Google Voice - Google Voice gives you one number for all your phones, voicemail organized in an email format, free...
TDS Business VoIP - TDS Business offers confidence in every connection through our business VoIP phone service options.
Mitel - Business Communications and Collaboration
Phonebooth - Phonebooth is one of the leading voip providers, providing phone systems & phone service for small businesses.
CSipSimple - CSipSimple is a SIP application for android devices.
VoIP.ms - VoIP.ms is a VoIP origination and termination tool.