I've been reading the Unplggd blog from Apartment Therapy a lot lately, because I recently moved into a new place and am trying to fill it up with cool stuff. And someone over there must be an iPhone fan, because I've seen not one but two great and simple tricks for the iPhone there recently. The first is the most billiant thing I've ever seen -- if you happen to be listening to music or a conference call through the speaker on your iPhone and need it a little louder, you can just find a pint-size glass, put the iPhone in there, and voila, simple iPhone echo chamber. I'm surprised at both how easy this is and how well it works, but it does. Very impressive.
Second is a little more obvious -- if you're using an iPhone to read off a recipe in the kitchen, with your hands messy and wet, you can put it in a baggie like I do, or you can CryoVac it, if you happen to have one of those sitting around. Either way, the capacitive touchscreen still works through a thin layer of plastic, and your iPhone will live to see another day.
Ok, so the second tip is not quite as great as the first one. But a pint glass! Trying to listen to all of those boring conference calls with my iPhone's speaker will never be the same again!