Spectrum scope makes it easy to compute and display the fft of a live signal. You feed it your time series data, and it does the rest. It works very nicely with the Timer objects introduced in R13, and with Analoginput objects (from the Data Acquisition Toolbox).
Here's a simple example, assuming you've defined a sample rate (Fs), a desired FFT length (Nfft), and some data (s) that you'd like to view:
%% Initialize scope
%% Update scope
I've included a few functioning examples to get you started.
I welcome your feedback.