Apologies if it's old news, but for those who fancy an old school cycling cap (ala Yehuda Moon ;-)), but can't quite find one to suit, here's couple of (ok, 3) links to plans so simple even I may be forced to stab my hands with needles in a vain attempt to emulate ;-);
http://www.flickr.com/photos/pandaface/278411178/?reg=1&src=fave
https://docs.google.com/leaf?id=0BzM6b0JN5CeyMWY3MzkzNjktNTMzMC00ZGY4LTlkYTktODFhNzFiMmRjODYy&hl=en