Sea Lemon: A fantastic youtube channel ran by Jennifer, aka Sea Lemon. There are some very easy to follow how-to videos here on bookmaking. Everything from making softcover and hardcover books, materials needed, sewing, etc. A great DIY resource.
Sage Reynolds: Sage is an artist designer with a talent for bookbinding. His youtube channel is a great resource for learning new bookmaking techniques.
iBookBinding: The site is a bit of a mess but these folks offer a wide range of resources on all things bookbinding. A great resource for online tutorials and bookmaking workshops.