I've placed this information here because I find that occasionally parents ask me for recommended URLs. As we all know there is a lot of good stuff and a lot of nonsence out there, especially when it comes to medical and/or parenting issues. When it comes to breastfeeding I give an endorsement to the following sites.

Real Life breastfeeding organizations that also have online content (I like to recommend RL organizations because it is so helpful to be around other mothers who are also breastfeeding and doing well at it)

http://www.iblce.org/ registry of US Lactation Consultants
http://www.llli.org/ international NPO, NGO for BFing support
http://www.nmaa.asn.au/ Austrailian BFing support
http://www.aleitamento.org.br/ Brazilian BFing support
http://www.breastfeeding.org.sg/ Singapore BFing support
http://www.breastfeeding.co.uk/bfn/UK BFing support

good URLs aimed at breastfeeding families (I like these sites because they have accurate information and some people just are not the organization joining type)

http://www.bflrc.com/links/parents.htm (list of links for parents)
(be sure to see Dr. Jack Newman's articles. Jack is one of the world's Great Men. He shares freely what he could sell, he has a killer sense of humor and he is wise beyond words)

free online course in the basic physiology of lactation
aimed at medical types but really good for parents and anyone interested in the human body and how it functions

PUMP COMPANIES:(I list these because many times consumers are not aware of the variety of pumps available)
go to your area, then products then breastfeeding

IMO, The best hand pumps are the "Avent Isis" and the "Medela Harmony" and the best bottle nipple for breastfed babies who must get a bottle early in life is the "Avent newborn" or "Avent single hole" nipple. (I tell you this because I am asked that question so often)

Other outstanding single issue URLs
Medication and Mother's Milk author Tom Hale's site - he updates his book almost yearly but keeps most recent updates on the web as well - a generous, wonderful man.

model hospital policy - Consumers (if you have been called a patient you are a medical CONSUMER!) We should all demand this level of care locally.

http://www.armsreach.com (commercial site but good product)

Co Sleeping with baby - research based information & products to facilitate safe parent/infant cosleeping http://www.babyfriendly.org.uk/bedshare.htm

www.snugglenest.com (commercial site but good product)

www.BFAR.org (breastfeeding after breast reduction)

USA Congresswoman Carolyn Maloney's summary of breastfeeding legislation (includes international as well as US national and state based work)

I love this woman AND the way she writes! If you read nothing else read Diane. She makes complex ideas seem so simple. She is also an excellant speaker with a cute southern accent.
Bonus - cute nature site by her husband on same URL.

breastfeeding from the view of an anthropologist, Dr. Katherine A. Dettwyler. Another must read by another person I love IRL.

Lactation related things I've written here:
crematocrit / breastfeeding / Giving a bottle to a breastfed baby / natural age of weaning / cleft palate / The medicalization of childbirth and pregnancy / premature baby / Poland Syndrome / male genital mutilation / breast pain mastalgia / supply and demand regulation of breastmilk / premature baby / formula / online information about breastfeeding for parents / Guide to Breastfeeding / afterbirth pain / moist heat therapy / beta-carotene / Breastfeeding the Newborn / Leche / lactation consultant / Feeding and Swallowing Disorders in Infancy: Assessment and Management / UNICEF / WABA / IBFAN / public breastfeeding / Medications and Mothers' Milk / Breastfeeding: Biocultural Perspectives / Apgar scale / Lactivist / attachment parenting / Breastfeeding Matters / La Leche League International / ear infection / nursing strike / Solomon / nipple piercing / milk / each one teach one / Sudden Infant Death Syndrome / fenugreek / lactogogue / Clinical Lactation: A Visual Guide / sub mucous cleft palate / The Breastfeeding Atlas / ankyloglossia / Tongue Tie From Confusion to Clarity A Guide to the Diagnosis and Treatment of Ankyloglossia / Current Issues in Clinical Lactation / peristalsis / BodyPerks / lactose intolerant / supplemental nursing system / at breast supplementer / How to Know a Health Professional is not Supportive of Breastfeeding / Lactnet / Breast Reduction / Clinical Therapy In Breastfeeding Patients / Killing baby bunnies with breast milk / Near term infant

This is all of course my opinion and not exclusive. There are TONS of other very good websites about breastfeeding. But because of a few bad ones I feel the need when working as a lactation consultant with breastfeeding couples (which is one of the things I do IRL) to provide a starting point of reliable information.
I'm especially interested in adding more non English based sites, if you know of any please /msg me.