To be more specific, find this section in the formmail script and adjust it as follows:-
sub send_mail {
# Localize variables used in this subroutine. #
local($print_config,$key,$sort_order,$sorted_field,$env_report);
# Open The Mail Program
open(MAIL,"|$mailprog -t");
##########################################
# print MAIL "To: $Config{'recipient'}\n"; # Disabled - recipient is hard coded #
##########################################
print MAIL "To: yourname\@yourdomain.com\n"; # Only this one valid recipient #
Don't forget to escape the @ sign with a \ backslash.
You can then alter the hidden field 'recipient' in your html form to a ficticious email address such as
noperson@nowhere.com. Of course, the action of the form must submit to your cgi-bin as before.