All web pages are written in this language, so understanding of it is critical to create web pages. HTML, unlike TeX or Troff is not hard to learn. The best way is to look at other people's HTML files and then start using peices of it in your own pages. If you are interested in a general reference on HTML, try the web. If you prefer reading about things like this in books, go to any good software bookstore and browse through their selection of HTML primers.
Web authoring is a hot topic, and there is a wide selection of materials available in printed form.
Unless you are working on a department-sanctioned project and have prior authentication, there is no way have your disk quota expanded for web graphics. Typically subscribers to UNIX shell accounts, such as those provided by these ISPs, are given a directory to place web documents. Alternativly, you can run a web server of your own and serve your graphics from there, assuming you have some form of direct internet access through some other party besides Brandeis.