Jonathan Geller is reporting that a source has told the Boy Genius Report that the new mobile hotspot feature that the Verizon iPhone has will be coming to all iPhones in iOS 4.3. Boy Genius Report has some solid sources in the cell phone industry and I wouldn’t doubt that this feature is coming to GSM iPhones as well. The question is whether AT&T will support it on day one or will they delay it like they did traditional tethering? And, will there be an additional cost associated with it or will that cost be included in the current tethering charge?