Is there anything online?

I have Healthy Sleep Habits Happy Child and The Sleep Lady and I've only checked the latter (the first is not at my house) and I'm not finding much that's useful.

The internet only seems to acknowledge that it exists and tells me nothing about how long it lasts or what I should do or not do about it. Most of the sites say if your baby hasn't learned to fall asleep on his/her own.... But my baby HAD learned that for months, and how has unlearned that.

Any useful resources out there? Any useful pieces of info?