Matching Moms helps you find other moms in your area that you have things in common with.
I took a breastfeeding class at the hospital that taught from one of Amy Spangler's books and it was very helpful.
I haven't personally used La Leche League's resources but I know ladies that have and I have heard great things about them.
I have read the Pearl's books on child training and subscribe to their newsletter. They have a lot of good ideas on training children and other practical advice.
Babyzone was very helpful when I was pregnant. It tells you how your baby is developing week by week.
This is my husband's site.