Being a teenage guy myself, I think steven (the above poster) is actually closer to the mark.
To the people saying "What you wear depends on why you wear it." Now, let's look at the example from holly (top of page 3)- She says that the body is beatuiful, and she doesn't want to cover up what God has made. Does that mean she should walk around nude? Heck no.
Likewise, if you dress in revealing clothing, whether you're being flirty or not a guy will fall into temptation. I try to watch my girlfriend in this- She normally wears a low-cut shirt with a tank over it, and while that's fine in most ideal situations, I have to remind her that... Well, she's short and very well-built, so taller guys (like me), can easily see more than they need to... Especially me, since cuddling on the couch or something (with others in the room) is something we like to do XD
As for specific guidelines- Your legs... Really shouldn't go above mid-thigh, though the LIMIT if you just HAD to wear something because it "goes with that and nothing else does" or whatever... My first recommendation is go buy something longer to go with it. The second is the extreme would be like 3/5 up. As for make-up, I honestly don't care. If you have to wear it to look decent, go ahead. If you just wanna look nice, go ahead. As a guy, I hardly notice make-up anyway, and any attraction it gives is more of a maturity factor than a sexual factor. And for cleavage... There shouldn't be ANY. Sorry for the well-developed ladies, but any skin in the chest area is too much. I'm not sure how accurate this measurement is since I don't really measure girls, but I think that probably 2-3 inches below the neckline would be the limit (maybe less).
As for the whole summer argument, there is NO time EVER where you have to wear practically nothing. I myself wear jeans and a T-shirt year-round, with a jacket in the winter. I have nothing against shorts (though I don't wear them myself), but I can assure you there is relatively no (temperature) difference between shorts above mid-thigh and shirts at the knees.
As for the whole "fashion" thing, I'm sorry it limits you. My girlfriend is into fashion, and today's fashion... Well, it's just too much for the average guy. She finds ways to still be fashionable while being modest though, so I know it's possible. Can't give you any specific tips on that, but I'm sure other places have that =)