Tired of seeing people write about VoIP as just a mere replacement for the current PSTN, Jeff Pulver (VoIP evangelist and the CEO of Pulver.com, the organizers of the VON show) took matters into his own hands and launched pulver.Communicator a new SIP client offering functions such as IM, social networking (users can share their buddy lists), and direct VoIP calls to SIP contacts.  The point-and-click interface allows a user to initiate a VoIP call with a SIP contact simply by clicking on that person's name on the buddy list.  Another nice feature is the support of multi-chat across different IM networks (AOL, ICQ, Yahoo!). 

The social network aspect is also interesting, since it can be used not only to share buddy lists, but also to determine who can call any given users (e.g. friends only or friends and friends of friends).  The "click to call" feature is carried over the SIP-based FWD (Free World Dialup) network.  There is an option to allow for inbound linkage from the PSTN via LibréTel, a service also offered by Pulver.com (available for a monthly fee ranging from $6 to $12, depending on the country).  There were some demos at VON for beta versions running on the Palm OS, Pocket PC and RIM's BlackBerry.