"Are you aware of whether or not there is such a thing as a company that offers a 'secure' conference calling service? A company that provides an 800 number that people can call in to and participate in a 'secure' multi-party conference call?" No one-stop solutions. How about a two-stop solution? Set up encrypted conference calls via VoIP using ZFone. Combine this with an on-line conference call service which uses Asterisk software. • Participant requirements -- Access to the Internet. -- ZFone software on their computer (lap or desktop). It's FREE. -- Optional, for added privacy:
--- A plug-in headset $3.99
--- Or, plug-in ear-buds $23.99 • Teleconferencing requirements -- Schedule calls with an Asterisk-based provider, like Rondee. It's FREE. (others) -- Major carriers offer secure 'web-meeting' services for a fee. (example) Note: Conference providers have access unencrypted calls; CALEA. Other options • VoIP telephony - Just route all calls through a Virtual Private Network (VPN). Good for inter-company conference calls.
"Very occasionally, there is a half second of delay when you have a few VPN-based users on a conference call together, but that has a nice social side effect of stopping people from trying to interrupt each other." Posted by Bradley M. Kuhn on June 20, 2008.
• Polycom Encrypted Video Conference Calling (Point to Point)
As I learn of new solutions I will let you know.
Until then, I hope this helps.
Kevin