Wikipedia as always provides a good start into the subject. Especially by the prolific amount of links to additional explanations, it is a great beginning to dive deeply into permanent magnetism as well as into related phenomena.
This site has many tutorials about electronics. The specific tutorial about electromagnetism provides 6 subtutorials with a large amount of very instructive explanations about magnetic fields, permanent magnets, hysteresis, magnetic fields of currents, magnetic induction etc. Of interest should also be the comment area, where one can leave comments and questions. Great for the beginners in electromagnetism !
There are many traders and manufacturers of permanent magnets who provide introductions and tutorials about permanent magnets. At this site a very nice and practically oriented introduction is given. Especially the different sorts of materials and how they are manufactured, practical handling of magnets, stability, coatings, design considerations and many more are provided. Very recommendable !
Literally a very cool website. Explains magnetic phenomena at real life experiments and provides detailed explanations about the major phenomena without demanding any math. Good for the beginner as well as even for the expert. Cool !