Bluetooth from arduino to iPhone?

What's the popular way to get this going? Software I can do. In fact, my sensor is working great on the table as I type. Its the wireless hardware I'm looking for. I assume there's a good bluetooth shield I could buy. Any suggestions?

Thanks!

-jim lee

Search "Serial Bluetooth RF Transceiver" on Ebay to keep the cost very low: it's easy and you can find some of these with the breakboard installed, so no solder needed. There're also shield like this http://www.seeedstudio.com/depot/bluetooth-shield-p-866.html: they cost a lot more even if they use the exact same bluetooth module, but it's "plug and play" and they are made for arduino.

I prefer the first one: it's the same thing for less than 10$ $)

Sorry for bad english :)... Bye!