I remember from 3 years ago that it was an absolutely huge pain to use any nice PNG with alpha in websites, because of IE6 and other bad browsers.
But how about now? How about if your target audience are iPhone, iPad and iPod Touch users? I believe these people aren't so stupid to use old-aged bad browsers. They use the newest, best stuff they can, and they're tech-savvy and intelligent. Is this an valid assumption? So does this mean I can safely use PNG with alpha to create great websites for my apps without having to worry about uglyness?
Yes it's absolutely fine to use PNG's with Alpha Transparency. It actually always has been, you just had to fix IE6 with filters.
So go ahead and use them :)