I did some packet sniffing on my Galaxy Nexus and the results are:
S Voice is definitely hosted at Vlingo servers IP address 126.96.36.199. Same IP address is used when I start using Vlingo.
IP address: 188.8.131.52
IP country code: US
IP address country: United States
ISP of this IP: Verizon Business
Second thing is that, at the moment we start using S Voice we are sending all the following info to them:
X-vlclient: DeviceMake=samsung; DeviceOSName=Android; DeviceModel=Galaxy Nexus; DeviceOS=4.0.4; Language=en-US; ConnectionType=DirectTCP; Carrier=[my Carrier]; CarrierCountry=[my Country]; DeviceID=[my IMEI]; AudioDevice=Android\r\n
...looks easy to them to deny the requests from the phones other than Galaxy SIII ! and they are doing this obviously, look at the response:
184.108.40.206 10.8.0.1 HTTP 340 HTTP/1.0 404 Not Found
Expert Info (Chat/Sequence): HTTP/1.0 404 Not Found\r\n
Comments, workarounds welcomed .
...the app was grate, I had the chance to test it for less than an hour, but one thing I noticed was that it was recognizing non english contact names.