The CGI Resource Index
A very useful site for finding CGI scripts. The scripts that are linked to are not all free, but if it costs money the price is listed below the link.
This is another great place to find CGI scripts for your site. You can even post a "help wanted" ad to see if someone else out there can make a script for you!
The CGI Directory
Hundreds of CGI scripts, tutorials, code, books, and other related resources.
The CGI-Index.com is a directory of over 200 categories of CGI resources. Includes listings of CGI scripts written in every language from Perl to C and C++ and from Visual Basic to Unix Shell-- as well as a number of other great resources. Also includes various CGI and Perl related tutorials and articles.
Matt's Script Archive
An excellent source for finding useful, free CGI scripts to use on your site. The scripts even come with excellent instructions on how to get them up and running on your web site.
A nice collection of CGI scripts to try out.