Obviously, learn the basics of HTML first, above all else - you can't do much anything web-based without it.
Simpler web design programming languages like Javascript and CSS are extremely easy to work with, because they're what are called "client-side" scripts - all of the work interpreting the program's commands are done by the person visiting the site, not the computer hosting it.
You'll want to get a start in CGI, PHP, and/or Perl as well, as those are server-side scripts, which are much more secure for sites that require logins, etc - hence, knowing this is worth much more to employers than just knowing client-side scripting.
These are only a few ideas, there's a WHOLE WORLD of programming languages out there, but you'll run into much more as you go along.
Hope this helps you get off in the right direction!