tuner programs

Does anyone know of any tuner programs (MSWin or Mac, I suppose) that have 
a graph of frequency over time, for the past few seconds at least?

Something like this tuner is interesting:
http://www1.ocn.ne.jp/~tuner/tuner_e.html
but I'd really like something that showed the frequency(ies) not just at 
the exact present, but also for the past few seconds.

The reason I ask is that besides my role in life as the ineluctable 
roustabout of Perldom, I do tech support for projects to study, preserve, 
and teach Native American languages.  A guy I know is trying to learn the 
system of tones in Cherokee, but he doesn't have much of an ear for 
it.  It'd really help to have a way to basically have real-time pitch plots.
--
Sean M. Burke    http://www.spinn.net/~sburke/