Japan's Ubiquitous Entertainment Inc. is prototyping an iPhone-based navigation system for cyclists. The "iPhone Arider" couples a stock iPhone with Scalar Corporation's model T3-A retractable head-mounted display. The handset runs the GPS app of your choice and routes the video to the eye-level viewer. Bikers can also make and receive hands-free phone calls via Bluetooth, and even use the TwitBird Pro app to get push notifications from their Twitter stream.
And for those who look at the picture above and question (a) the helmet-mounted — and otherwise unprotected — iPhone and (b) the safety concerns of a heads-up display of any kind, repeat after me: "Prototype. Prototype. Prototype…" Everyone else can watch this video of said prototype at work: