Grinder is right on with this advice. I went through this same learning curve earlier in the week in this node and am loving Mail::Sendmail, thanks to him.

You use of $formdata looks strangely like what I used to do when using someone's handrolled form parser (this bad practice is propagated in The Perl and CGI Visual QuickStart Guide for one). Don't do it! Listen to the good monks here. Use CGI!!! And if you are doing much web work, I have one module for you: HTML::Template. It's wonderful.

You will see lots of encouragement to use strict; use warnings; etc. All a bit daunting at first, but learnable with the help of the folks here at the monastery. I have found lurking around here invaluable.

You will also see lots of references to Learning Perl and Programming Perl. I also recommend Programming CGI (all aforementioned are O'Reilly books).