Although this isn't the first VoIP solution for the iPhone (that belongs to either SoonR or that one videoconferencing winner), TruPhone seems to be the most elegant (in theory) VoIP app so far. Although the service is really early on in its development stages, the end product will be able to switch seamlessly between VoIP calling on Wi-Fi and standard calls using your SIM whenever you're in Wi-Fi range. Not many details are available about how they're doing this, but we're watching intently. [TruPhone via Blognation]