Unicode has always been a bit misunderstood even by professionals. This is why several years ago we pulled these slides together to clear things up. The presentation is a bit old but still relevant. You may still learn a few things about Unicode that you did not know.
BTW, today we are pushing a lot of our slides to Slideshare. You can find our profile page here. So far you can find some presentations from past conferences and of course our Web Application Security 101 course, which we do once to twice a year.