I recently took part in an episode of the Telecom Junkies podcast entitled "Holy SIP! It's VoiceCon." which is now available. Host Jason Huffman interviewed both myself and Ken Agress of PlanNet Consulting to get our thoughts on VoiceCon and topics including SIP and VoIP security.
The podcast turned out well, but my comments contained a lot of static. It looks like using a bluetooth headset with a Treo isn't the best way to achieve high voice quality (especially when you are using a laptop also running bluetooth and WiFi).