10:20AM – Apps talk to accessories via the dock connector and via Bluetooth. Supports standard protocols (playing music, album artwork, etc.) and you can build custom protocols.
“With iPhone 3.0 we’re going to take this to the next level: we’re going to enable devs to build custom accessories that talk right to the iPhone.” This is exactly what people have been wanting. “You can give the iPhone an equalizer to a speaker system. Here’s another example: FM transmitter, which would find the optimal broadcast channel and play your music. Here’s another class we think will be interesting: medical devices.”
… so you can’t just hook up a gps without some extra firmware/microcontroller to encapsulate the data (and also to ID the dongle, so that programs know what is connected). But, I haven’t seen much info on this, so it’s mostly speculation until apple gives more details.
Alas, it does appear that all dock/bluetooth accessories must be officially licensed under the “made for iPod” program which seems to require the use of an auth chip (and, I assume, some sort of auth protocol for BT) so it may not be as simple as I had hoped. The iPhone does speak pretty standard serial, but to get at it, you must go through the frameworks which only let you speak to authorized devices. Of course, the jailbreak community may fix all this. I know I would love to be able to use an iPhone/Touch as a very rich control and feedback/display device for all sorts of projects!
For Makers, perhaps some old school modem hacks are in order for I/O using audio in and audio out? No apple auth chip needed there.
I really think a add-on key board would really kick sales into overdrive for the traveling business person. Even a medium sized keyboard with a swivel stand for the phone would be perfect for the new 3.0 with all the landscape keyboard changes. They could even add a batter to the keyboard.
Pre-charge the keyboard to give the iphone extra power and a keyboard while your flying. No cables needed.