I’ve been playing a great deal with Arduinos lately, and have acquired a couple of Xbees to experiment with wireless. But Xbees, cool as they are, are kind of expensive for many tasks where a much simple RF link could suffice. Today, I ran across the JeeNode, which is available as a kit from Modern Device for just $22.50, and that includes a 915Mhz RF link. You’ll need an FTDI cable to program it, just like any other low cost Arduino. Pretty neat!