The Scout Observer by Scout is an iPhone dock that is a bit too pricey and sophisticated for most of us. It's a six pound box designed for the military that turns into a portable satellite communication terminal when it's mated to an iPhone 4.
It offers a spectrum analyzer, power meter, multimeter and a block downconverter which lets you locate and measure satellite signals.
No cost is given for this mean machine yet. Tt's scheduled to ship in the 4th quarter of 2011. Note: The direct link to information on the Scout Observer seems down for the moment. Hopefully the device will work better than the website. Here's a link to the general company website.
Apple iPhone 6