Via Gabriel Kent.Maybe I am a bit late on this very concept. Seems interesting, Voice Over General Packet Radio Service could be seen as:

Of course we see Voice Over Internet Protocol (VOIP) movement in the mobile space with the creation of WIFI Phones and such --- however, we are also seeing some take advantage of the rich toolkits already offered by many smart phones (Pocket PC/Palm/Symbian etc Phones) to create VOIP capability. Nonetheless, most of this movement is focused on VOIP and therefore WIFI as some of these smart phones are equipped with WIFI chipsets.

While VOGPRS is not that far of a stretch from this current industry focus, it nonetheless opens the door for current (and near future) smart phones to take advantage of cheap voice calls to anywhere in the world from anywhere in the world (where GPRS is available) and not be confined to small WIFI spaces.

While GPRS has a theoretical maximum of 171.2 Kbps, I usually obtain about 100 Kbps over Verizon's GPRS network. Following my previous work with CELP, I can tell you a 16 Kbps voice stream sounds quite intelligible. Assuming 32 Kbps is required (bi-directional voice streams) for our conversation, then it would most likely hold up well even while driving down the freeway.