You can write server side CGI-BIN programs in any interpreted or
compiled language available on your server. The most commonly used
languages are C, Perl and Bourne Shell. There are many repositories with
useful scripts and include libraries available in several sites. Look
under the CGI section in Yahoo or search for the keywords: forms, cgi.
If you decide to use Perl, there are some useful libraries and utilities
There is also a C library at:
and a nice tutorial at: