Really cool new way to monitor ovulation is coming to the US. This device has been available in Europe since 2009. Check out this Youtube video to watch a demonstration: http://youtu.be/Eu70WJ_k4Aw
A sensor is worn under the armpit and measures subtle changes in basal body temperature which is indicative of ovulation. The reader wirelessly receives the sensor data and predicts when you are most likely to become pregnant up to six days in advance. A number of additional parameters can also be entered into the reader unit to improve the prediction quality. The recorded data can be visualized by connecting the reader unit into your computer. Cool stuff!