If you are interested in websec (web security) you should pretty much understand the different protocols on the web, i.e TCP/IP, FTP, HTTP, SSH, etc.
Knowledge of HTML, PHP, ASP, SQL, Perl, and Python is good.
HTML: http://www.w3schools.com
PHP: http://www.php.net
ASP.NET: http://www.asp.net/Default.aspx?tabindex=0&tabid=1
SQL: http://www.mysql.com
Perl: http://www.perl.com/
Python: http://www.python.org