How to Secure VOIP

CIO Magazine has a 5 page article on VOIP Security. "Voice over IP offers great savings in long-distance calls. But without extensive safeguards, VoIP can expose your phone system to the havoc affecting the rest of the Web." "Traditional private branch exchange (PBX) phone systems have their own vulnerabilities, and in the past hackers have broken into large phone and voice mail networks. But VoIP expands vulnerability, offering more opportunities for hackers to gain access."