One of the great things about cgi.pm is that all the code remains the same whether you use get, post or something else
small example
Let's say you have a form with the fields name and email and you inlcuded some info in the link like this http://somewhere.com/index.pl?unique_id=1092384
to get name, email and unique id into vars you could use something like this.
#!/usr/bin/perl -w
use CGI;
my $q = new CGI;
my $name = $q->param( "name" );
my $email = $q->param( "email" );
my $unique_id = $q->param( "unique_id" );
just name the thing inside the ( " " ) the same as the name of the field you want to get, that all for today!
Imagination is more important then knowledge -Einstein-