This is great project for you if you make RF related projects. Working with signals is much more easier when you see them – especially if these are high freq. When building RF embedded applications you usually use standard modules that have standard frequencies like 433MHz, 868MHz and so on. So why not to use one of these modules to analyze spectrum of close frequencies. It can be done by using one of cheap RFM12B modules which can be easily interfaced to MSP430 MCU via SPI interface.
Module frequency can be configured in steps depending on bandwidth chosen. Currently spectrum analyzer is set to read 916MHz bandwidth with sweep of 241 120kHz steps. And this is right all that TI Launchpad USART 9600bps bottleneck allows. USART sends sends spectrum data to Perl visualization script where graphs are nicely seen along some effects like Peak Hold or Zooming. You will find there a detailed instructions on how to set up such spectrum analyzer. An yes – this is done under Linux.