The only place I know where to get more information on what you are looking for is on the google.Com. That is where I go to look the things I need more information on. Of course there is also yahoo and I am sure there is plenty of places. You could also ask your doctor for some information to. I hope this helps you some.

Fertilityfriend.Com is a great source for nfp.

There are some great books such as the art of natural family planning and taking charge of your fertility (haven't personally read the second one) that are very detailed. The art of nfp, specifically, has one or maybe even three entire chapters about using this form of birth control after having a child.

I found it really hard to find consitent information on the web. There are always varying ideas on things like this, such as what's better, what's easier, more reliable, etc. It's something you'll just have to find out for yourself through experience. You may find that after trying something for a while, you get really comfortable with knowing your body and when you ovulate (the time you are able to get pregnant) and don't need all the safe guards (like a fertility monitor, charting, etc.) that you did initially.

There are a lot of women on these boards who have been in your shoes or are there now, so just keep asking questions!