I've used a freeware program "visual analyser" by sillanium software, which turns the computer into an ocilloscope, to do similar things, but depends on your soundcard. But with a decent microphone it can be very handy trying to work out when things are happening in the engine cycle. Also it is a fun toy, but I've found it takes a while to get the hang of it.
I'm enjoying Mark's habit of not taking things as gospel, also it is fun, now where did I put the popcorn?
