I have just finished my driver for Nordic nRF24L01+ module. I saw that FEZ is missing a simple wireless solution. This module was once referenced on TinyCLR and in beginners book but the source code was very simple and only for the older version of the module (without the plus). I was using XBee before but found it to be a performance and price overkill for most of things i need. Nordic module is simple, cheap and reliable at the same time. If you are interested in testing it you can find the source code on Codeplex:
Here is a quick proof of concept. You can find details about this SimpleApp on project site.