Over on the Voice of VOIPSA weblog, security researcher Shawn Merdinger is 2/3 of the way through a series of posts on the “top 11 VoIP security issues you need to discuss with potential vendors”.  His posts are:

• Pucker Up – Intimate VoIP Phone Security Questions, Part 1 of 3 (1-5)
• Pucker Up – Intimate VoIP Phone Security Questions, Part 2 of 3 (6-8)

with the third post coming at some point soon to cover points 9-11.  Shawn’s posts are definitely “required reading” for anyone working on or concerned about issues around VoIP security.  He’s done a great job bringing into one place the many questions that you should be asking VoIP/IP telephony/IP communications vendors about the security of the systems you are considering (or have already deployed).