The BabyWearer: the best source of information for all things babywearing. Reviews of different carriers and vendors, directions, a great forum, and scads of other stuff. (I'm listed as sleeping baby productions or SBP, and post as Jan Andrea.)
La Leche League International: the most well-known pro-breastfeeding organization; provides free and useful information on breastfeeding issues.
misc.kids.breastfeeding (MKB) newsgroup: A usenet group devoted to topics concerning breastfeeding. This newsgroup has been absolutely invaluable to me, and I highly recommend it if you are pregnant, nursing, or partnered with a nursing mother.
Plus-Sized Pregnancy Website: If I were religious, I'd call this site a godsend for zaftig moms-to-be. "Kmom" has compiled tons of information on what to expect, finding a size-friendly practitioner, nursing with big breasts, and lots of shopping resources. I found it absolutely indispensible while I was pregnant.
Gentle Christian Mothers: Friendly, Christian-oriented attachment-parenting forum and website. A nice change from supposedly Christian parenting "experts" like Ezzo (who, in a nutshell, believes babies should suffer because Christ did). (Hey, I may be an a theist, but I know not all of my readers are :)
Nandu sewing patterns: Andrea Noll is a Hungarian mom, midwife, and seamstress. She offers a number of patterns for parents and kids.
Tardive dyskinesia: "Tardive Dyskinesia (TD) is a result of damage to the bodily systems that process dopamine, and is typically caused by exposure to certain prescription medications - including Reglan. Reglan is sometimes prescribed to women who have nausea or trouble lactating during breastfeeding, without properly being informed of the long term side effects. The symptoms of TD, which are irreversible and incurable, mimic those of Parkinson’s disease. Tardive Dyskinesia victims suffer from involuntary, repetitive movements which often continue after the drug is no longer used. We feature the most up-to-date information on TD, its causes and all known treatment options. Additionally, we distribute free support books and informational packets to our users." (I didn't know about this as a side effect of Reglan. Worth looking into if you're considering using Reglan for lactation issues.)
Babywearing: Talk about babywearing, favorite carriers, etc.
Babywearing Swap: Carriers for sale or trade
Sling Sewing: Talk about sewing carriers, patterns, etc.