PERL [google.com]
I'd also suggest having something you want to accomplish with Perl before starting. For example, what do you want to do with Perl? Do you want to write system administration scripts, or CGI scripts? Pick something that you'd like to do, go hit one of the big free Perl scripts sites, download a script, and look it over to see if you can figure out what it's doing. Check out the perl documentation as you go to explain what you're looking at. Maybe try to modify the script a little to get a feel for how the code works.
I found the best way to learn a language was to start with some simple code, figure it out, and start making changes to it, but then, I have more of a "learn by example" kind of mindset.
JK