I'd like to use an iphone to monitor output from a remote source using an xBee modem (or other low power wireless device). Ideally, the iPhone can regularly poll the XBee for this information and then use it to display generate output.
This is similar to the way the Nike+iPod thing works I guess but I was wondering if it was possible without the use of the edge-connector attachment?
not without resorting to a jailbroken device. bluetooth on iphone 2.x and 3.x devices is purely for handsfree. i've heard of people fooling to work with other audio devices, but that's the extent of bluetooth connectivity.
you want to use a data broker like pachube.com to view your sensor data via http. here's an example iphone app: http://apps.pachube.com/iphone/
Use the External Accessory Framework,
3.0 devices can check out the 3.0 SDK External Accessory Framework, It's still under NDA so cant share any code but it is possible.
The External Accessory framework provides a way to communicate with accessories connected to an iPhone OS based device. Use it to interact with accessories connected through the 30-pin dock connector or via Bluetooth.
XBee is 2.4GHz, but it's not WiFi or Bluetooth. There's no API for controlling the iPod's radio at that low level. If you want to talk to an XBee network, you'll need to connect via some sort of gateway device that sits on both the XBee network, and one of the networks connected to the iPhone. That could be either the Internet, LAN, or via a physical connection to the dock connector.
If you're comfortable with hardware, you could build a device with an ethernet jack and an XBee radio, and then write software for the iPhone to talk to your gadget, which would pass your messages onto the XBee network.
Or you could build your end node devices to use WiFi directly, leaving XBee out of the equation completely.
I know this is a bit old now, but I recently did a project that used an arduino with a WiServer shield that allowed me to present an ad-hoc network and webpage that could be viewed from my iPhone. I am using it to manage servo controls via GET requests to the web page.
Check out Async Labs for the WiServer stuff. They are in the process of releasing a combined arduino+WiShield product (Black Widow or yellowjacket, depending on your size needs).
Async Labs http://asynclabs.com