I really like this widget for jquery. Its such a nice and clean way to pick dates. So I went ahead and created a YUI 3 widget that does roughly the same thing, but with way fewer features at the moment. Anyway, the basic are there. (its slightly wonky in ie6 right now…)
Check it out here, or download the code here
UPDATE
Thanks to @ls_n, now it handles 12 hour time properly, for some reason I put 0 and 12…d’oh.