Lesson 2 was very good. Nice work, again.

I don't have CSS (cascading style sheets, right?) on my Netscape 3.0 (on IRIX 5.3) but it looked really good. No background colors, but the tabbing was perfect and the new little badges looked good.

Some minor things:
1) In Lesson 2 in the Why should you use CGI.pm section, I think you're missing a closing ) after "there is more than one way to do it."

2) In the Query string ignored on POSTs section, in the third line you have "The above code with detect..." and you probably want will instead of with.

3) In the second paragraph of the Exercise, you're missing the word "what" after "in case you need help remembering..."

Finally, having been around Perl Monks and read the Book Reviews, I know that Castro's book is horrible. But you never explicitly say it. You use bad code from the book, but someone may think that the book is another reference for CGI programming (which I guess it is, but you probably don't want to promote the book after you've spent all this time trying to teach us good habits). Again, thanks for all the work. It's looking great.