Recommendation for WiFi module

I am looking for a module that will ONLY receive Wifi (receive a signal to turn on/off a switch). I do not need the module to transmit to wifi. Any recommendation on a low cost module to accomplish this? if transmit is needed to establish communication, what is the minimum module to achieve very simple on/off signaling?

This will be the best WIFI Module you could find, once the driver is finished… Valkyrie has done some amazing work so far …


Thanks Jay Jay. Do you know if it will be supported with the FEZ Cerberus?

The intent is for the driver to work with any .NET MF device with SPI, which certainly includes the Cerberus. Most of my development is based on a CerbuinoBee. Once the driver is done it will easily be the least expensive Wifi solution.