Maricopa Community College has an online course to teach HTML.
"WRITING HTML WAS CREATED way back in 1994 to help teachers create learning resources that access information on the Internet. Here, you will be writing a lesson called Volcano Web. However, this tutorial may be used by anyone who wants to create web pages. You can get a sense of the results by looking at our illustrious alumni and kudos or what people say about the tutorial.
By the time you have reached the end of this tutorial you will be able to construct a series of linked web pages for any subject that includes formatted text, pictures, and hypertext links to other web pages on the Internet. If you follow the steps for the Basic Level (lessons 1-14) you will develop a page about volcanoes and if you go on to the Advanced Level (lessons 15-29), you will create an enhanced volcano web site."
Start learning HTML here.