Kellymom is my go-to resource for breastfeeding information. There are dozens of informational pages related to breastfeeding, including milk storage, average milk intakes, weight gain charts for breastfed babies, etc. This link sends you to the list of articles specifically about breastfeeding but there is also information about loads of other things parenting related so if you've got 3 hours to kill go get lost in this website.
This site has videos that can show you exactly how a great newborn latch should look. If you're trying out breastfeeding for the first time or are a veteran, a refresher of the newborn latch can be very helpful. There are also visuals regarding lactation aids, cup feeding, and tongue tie revisions. If you are having concerns about your baby, this is a good place to start.
Here is a link to the videos:
Here is a link to a list of articles related to breastfeeding. There is a lot of variety on this site including nipple ointment recipes, jaundice, starting solids and engorgement. These articles are a little quicker to get to the point than the Kellymom articles and can be helpful if you're looking for very succinct information.
Center for Disease Control (CDC)
If you're looking for the national recommendations, up to date research and resources from a government entity, here is the link to CDC resources on breastfeeding.
This is a very comprehensive 10 minute video about how to latch the baby. This video has many examples of what to look for as you latch your newborn. There is good visual representation of the anatomy of the mouth of the newborn to help you understand the correct positioning of the baby's mouth, chin and shoulders.