Apple has done banner ads in the past. I remember a particularly attention-grabbing campaign they did a few years ago on the NYTimes home page. It was a fairly creative piece.
Yea, I have only seen their banner advertising on large established media brands (probably kicked in as part of print or TV campaigns). Apple is old school with advertising, Steve was intimately involved in creating the advertisements and I'm sure in placing them.
Apple does do some AdWords advertising (I see an ad pointing to Apple.com when searching for iPhone), but I have not seen any Apple video ads on YouTube. Perhaps that's because they don't want to pay Google any more money than they have to.
