XHTML is HTML that is well-formed and valid XML. HTML (Hyper Text Markup Language) is the language used to define the structure of a web page.
I am currently using XHTML 1.1 standard where appropriate. If using tools that do not support XHTML, HTML 4.01 Transitional is the fall back.
I started coding HTML in my own time in early 1996. We were given some introductory classes at uni as part of the Multimedia degree, but by then I knew the basics. In February 1998 I began working for Squirrel Internet as a web developer, part-time from home. In November I finished my degree and took on the role full-time, contuining when Squirrel launched the Jumbomall until June 2000.
Most recently working as Web Content Master for Education Queensland, I have been looking after web architecture and publishing standards. For this, I keep a close eye on the web standards and trends, particularly W3C initiatives.
I am fully familiar a number of HTML editors and can easily learn new ones. My preference is for Allaire Homesite, but I have experience with Dreamweaver and Front Page.