PHP
http://www.php.net/
The CGI specification
http://hoohoo.ncsa.uiuc.edu/cgi/interface.html
ASP.NET
http://www.asp.net/
The original NCSA CGI documentation
http://hoohoo.ncsa.uiuc.edu/cgi/
CGI.pm
http://search.cpan.org/dist/CGI.pm/