Someone posted this awhile back, but I feel it is worth posting again.
Living the Sacrament is a Catholic NFP forum (all types of NFP are represented, CCL STM, TCOYF, Creighton, Billings, Marquette, etc.--and no one is better than another fights!) that I have really grown to love this past year. It is a wonderful group of ladies and a great resource. I highly recommend it to any Catholic couple investigating, learning, or practicing NFP!
http://livingthesacrament.com