This is really one nifty setup. First of all, it's a box that everyone and their dog would identify as a phone. It doesn't need a computer to be around, it's not a black box with a headset (although it supports the same headsets our standard desk phones support). It's just a desk phone that works like a desk phone. It's designed (only) for corporate use, so it's not "Internet calling" or anything like that. What it does do is this: You plug it in somewhere that is Internet-connected and provides DHCP -- even behind a NAT gateway -- and it works identically to the way it would work on your desk at the office, with no interaction at all to get it started. And the control and data connections between the phone and the office are encrypted, so you don't need to establish a VPN from wherever you are to the office to keep things secure.
It sounds simple, but this thing sells itself. A salesman who's often on the road gets his usual extension, voicemail, and presets at the hotel and at the trade show without having to co-ordinate anything with the hotel or trade show staff beyond an ethernet jack; support people can work from home without having to route calls over PSTN; people can switch desks inside the company and out to non-VPN'd branch offices without rewiring or repatching; and all of this without having to train the users anything beyond "plug in the cable".
(On the office side you've got one of our ICPs (IP PBXes, if you like), with a 6010 Teleworker Gateway between the ICP and the Internet; the phone is programmed to talk to the 6010, which performs the necessary magic to get it up and running. The 6010 is based on the 6000 Managed Application Server, which used to be the e-smith server and gateway, so the teleworker project was the one that kept my group around and me in work.)
One interesting part is that I don't think this would sell as software or as a software and peripheral bundle; people don't trust soft phones yet, because they think that hardware shaped like a phone is reliable and hardware shaped like a computer is not. "You plug in your phone and it just works" is a much more impressive pitch than "This software works from anywhere!", even though the software is easier to carry around. The secret to practical VoIP is to make it act like it's not VoIP at all.