These are two great online resources for predicting and confirming ovulation and helping to determine your best chances of getting pregnant.
Both have the same base, you can chart your temperatures medications, cervical fluids, symptoms and your period (length and flow strength).
Each one is different in their own way and you have to look at and experience both before making your final decision.
Here are some threads on other boards about FF vs TCOYF on BabyCenter, WhatToExpect.com and even on TCYOF.com.
Personally, I have read TCOYF but I use FF. As of now, I do not take my temperature, use OPK's or check my cervical position, so it's very basic for me. I follow my days, my cervical fluids and sometimes my "symptoms".
Taking Charge of Your Fertility:
Both sites are very user friendly, have forums and great tutorials. FF provides classes to get you started with charting and TCOYF has the book that is available for purchase. Whether you want to do a lot, like those pictured above, or a little, like me, there's a right match for you.
Have you looked at both? Which one is your favorite and why?