Arduino Simple Finger Pulse Reader

Hello All, Basically all I need is a simple pulse reader employing the low tech combination of an LED/IR LED and a photo resistor to monitor the blood pulsing through the finger and translate it into BPM. So just a low tech pulse oxymeter. All I want to do with this is simply create an arduino sketch that turns on an LED when the users bpm is over 80. I already have an Arduino Duemilanove, photo resistor and a bunch of other bits as per the attached photo but don't have the time to research and build. All you would have to do is create this your self on your own Duemilanove/Decimilla and send me a photo with detailed instructions along with the processing sketch (I'm working with Arduino 0017). Please make sure you solution is efficient and easily allows itself to be modified aesthetically (this is very important to me) but obviously I will be placing it in some sort of tube structure to remove ambient light. Also it must be fairly accurate within what the technology allows (I'll be checking it against my own pulse watch) I believe this is the photo resistor I have [login to view URL] I've also found a tutorial that even includes code! [login to view URL]