Is it okay to learn XHTML without having any HTML knowledge at all? Do you think learning to hand code html is necessary to be taught in a Web Design class rather than directly proceeding to tools such as Dreamweaver?
I suggest that you ditch Dreamweaver, since such "WYSIWYG" only tend to cause problems, usually they also add alot of obsolate code to your documents.
Most websites designed with such applications, is poorly designed, in the forms of locked font-sizes; incorrect code; over-useage of frames; bad cross-platform/browser support.
There are many websites, which holds Tutorials/References for HTML and CSS, some of them include:
http://www.w3cschool.com/ – (tutorials/references)
http://www.w3.org/MarkUp/Guide/ – (Dave Raggett’s Introduction to HTML)
http://www.w3.org/Style/Examples/011/firstcss/ – (Starting with HTML + CSS)
All you really need to create website’s, is a copy of notepad, or notepad++ (But generally any Text-Editor would do). See also: http://notepad-plus.sourceforge.net/uk/site.htm
Learning XHTML isen’t that important, the differance between html and xhtml is minimal, you can allways update your pages later, with less to no effort.
A serious Web-design class, wouldent even tuch the "WYSIWYG" editors. Its more then enough to know they exists, having that seid, alot of text-editors, have programming tools, which will speed up, (or even replace) many of the tasks, which you would otherwhise do manually.
Support for xhtml is poor, causing some browsers to render pages as text/html, instead of appcication/xml.