I'm several weeks late on this, but in case you hadn't noticed, this year's One Page Dungeon Contest has wrapped up, and the winning submissions are available on the wiki. There's a nice summary on Greg Costikyan's Play This Thing.
The One Page Dungeon Contest is a wonderful exercise that forces contributions to combine various aspects (design, story, technique) of the dungeon-maker's art into a single compact format. As with a number of creative efforts, the discipline of constraining yourself to a single page has a number of benefits, most importantly it forces you to focus and simplify and identify the essence of your idea.
As Einstein's wording of William of Occam's principle as it: everything should be as simple as possible, but no simpler.
I find that this paring-down-to-the-essence technique works wonders in software engineering, too, by the way. When you are concentrating on a bit of code, the question you should always have in your mind is not "what can I add?", but rather "what can I take out?".
But back to dungeons.
I think that the best way to enjoy the One Page Dungeon Contest is to look through the winning submissions, find one which appeals to you, and then look at the bottom of the campaign wiki where the committee has cross-referenced the supporting essays, articles, and blog posts from the authors of the dungeons.
For example, here's the nifty Citadel of Evil, by Stuart Robertson. It's gorgeous, but what's even better is Stuart's blog post, where he goes into a nice explanation of the "pocketmod" format for packing a booklet into a single foldable page with some great references to other uses of that technique.
Similarly, Aaron Frost and Mundi King provide a nice explanation on their web site of the evolution of their design from an idea that was too large to fit down to the gorgeous final result.
Happy dungeon reading!