Just thought I share a few resources I've found useful during my research so far into iBeacon and Bluetooth LE technologies.
My interest in iBeacon development was initially piqued by this piece from Tony Smith on The Register.
Having a Raspberry Pi spare, I followed Tony's instructions and soon had a beacon up and running...well, as soon as the Bluetooth dongle I ordered via Amazon arrived.
Tony mentions Radius Networks in his article and references this page, which features an in depth (but easy to follow tutorial) on setting up a beacon and goes on to give instructions on scripting the beacon to come up automatically when the Pi is booted up.
Radius Networks also provides free applications for iOS and Android that you can use to locate nearby beacons. I have so far spent many happy hours walking into and out of range of nearby beacons, and marvelling as detection and ranging events pop up in real time; I am clearly spending far too much time indoors. It's also worth noting that the iOS version of the app is capable of acting as an iBeacon in its own right.
If Android is your platform of choice, the Radius Networks Android iBeacon Library (basically a free Android SDK for working with beacons) is worth a look...and finally, you could definitely do yourself a favour by taking a few minutes to look at their developer blog.