Date controls for Silverlight
Waiting for real 1.1 input controls, we can find some custom projects; Kathy Kam made 2 great controls for Silverlight 1.1: MonthCalendar and Datepicker. Download them for free on her blog post :
MonthCalendar and Datepicker control for Silverlight
Read the complete post at http://weblogs.asp.net/lduveau/archive/2007/11/08/date-controls-for-silverlight.aspx