You need a digital or a special Basal thermometer.
Try registering here
http://www.fertilityfriend.com/you can note your temperatures down each day and other signs like your cervical mucus. I have just started doing it. your temperature rises after ovulation so you need to chart them for a couple of months to get an idea when you ovulate.
[Modified by: beanz on March 28, 2008 02:55 PM]