A beginner's guide to HTML is available at the URL http://www.ncsa.uiuc.edu/General/Internet/WWW/HTMLPrimer.html . You can also find a compressed Postscript version (at the URL ftp://ftp.ncsa.uiuc.edu/ncsapubs/WWW/HTMLPrimer.ps.Z). (Since the latter two are FTP URLs, you can fetch them by hand using FTP if you do not yet have a web browser.)
There is also an HTML primer by Nathan Torkington at the URL http://www.vuw.ac.nz/who/Nathan.Torkington/ideas/www-html.html .