Overview
History shows us that advances and trends in information technology typically outpace the corresponding realistic security requirements, which are often tackled only after these technologies are widely deployed. Voice over IP (VoIP) is no different. As VoIP's popularity increases, so will its exposure to current and emerging security threats.
The Voice over IP Security Alliance (VOIPSA) aims to fill the void of VoIP security related resources through a unique collaboration of VoIP and Information Security vendors, providers, and thought leaders.
VOIPSA's mission is to drive adoption of VoIP by promoting the current state of VoIP security research, VoIP security education and awareness, and free VoIP testing methodologies and tools.
They have a blog here also..