Nobody has seen the new IP Communicator for Vista yet. You might be able to get some kind of SIP generic phone to work with SIP CCM 5.0 or CME... I havent tried that yet. I would assume if have connections to Cisco SE's and your Sales Team, they will let you know when the IPC will be out for beta or public release with Vista.

Vista has some new quirky networking that restricts how IPSEC works now. It's causing audio issues from what I understand.