Thoughtlessly applying techniques effective in one language to another typically leads to awkward, poorly performing, and hard-to-maintain code. Such code is also most frustrating to write because every line of code and every compiler error message reminds the programmer that the language used differs from "the old language."

-- Stroustrup, The C++ Programming Language, 4th Edition

I suggest the best approach to teaching Perl5 developers how to use Perl6 is to teach them Perl6 with the expectation that they are programmers, who are capable of picking up new languages. It's not very useful to me to learn how to translate Perl5 idioms to Perl6. Show me Perl6 on its own terms.

When I pick up a book on Scheme, or JavaScript, or SQL, or C++, I expect to be introduced to a new means of expression in programming, and am glad that I don't have to sift through examples of how to do Perlish things in C++. I (hopefully) get exposed to the new language as a complete entity that needn't compare itself to other relatives no matter how close they are.

The occasional "In contrast to XXX, YYY." is fine. But think of the best programming books you've read. How many of them focus mostly on comparing and contrasting? The Perl Cookbook doesn't start each chapter by saying, "In C I would do yada yada, how do I do that in Perl?" Mastering Algorithms with Perl doesn't bog us down with example of how graphs were implemented in Java.

Ok, enough of that.... now for some words of encouragement.

It appears that Perl6 is on its way to becoming a fairly nifty language, with lots of cool features. It would be great if there were some well written literature to go along with a complete implementation. I look forward to both.