Xin's Popup Calendar makes inputting dates into forms as easy as point-and-click. Your user simply selects the date from a popup-window calendar, and it's automatically entered into the designated form field. This is one of the absolute best script of its kind, with the following noteworthy features:

+ Customizable date format (ie: y/m/d, m/d/y etc).
+ Fully customizable interface (colors, popup window dimensions etc).
+ Accommodation for different languages other than English and English calendar format
+ Fully cross browser functional- IE4+/Win, IE5+/Mac, NN4x, N6+, Opera6+/Win and Konqueror3/Linux.