I use TCOYF (which stands for Take Charge Of Your Fertility) Its a computer programe, I cant rember how much it cost, I know it wasnt to bad. I have it on my laptop and it records everything, tells me when I m expected to ovulate months in advance and then has everything from that point on. I just entered into it when bubs would be due if I conceived on the 10th of July.... guess what.... APRIL FOOLS DAY....LMAO... thats when my eldest son (now 19) was due..... he ended up being born on the 4th April.