I would also suggest you learn HTML prior to learning HTML5 as it's really the backbone of how HTML5 progressed and most of the fundamentals of web design are gleaned from the earlier versions. Although HTML5 is definitely much different in many ways from HTML 4, it's definitely the same structurewise, just a lot different in naming of it's structuring and has a lot more to offer. This site might help a bit:

http://teamtreehouse.com/

Good luck