ASP.Net Date & Time Pickers
One of the best and simple to use http://www.markbeaton.com/SoftwareInfo.aspx?ID=868292da-e93e-4e85-b455-41263ed15cd5 List of various calendar controls from ASP.Net http://www.asp.net/community/control-gallery/browse.aspx?category=52 Ajax based controls http://www.michaelkbell.com/timepicker/