I am using asp.net 2.0 c#. I am trying to allow the user to click a
botton and open a new window (page) with only calender control on it.
this window should has no bars (menu, or tool) just the close or
minimize buttons. when they select the date from the calender it pass
the date to my text box in the first page.

may i suggest using this free date picker asp.net control instead.  it
offers more features than the calendar control included with asp.net
and provides good cross browser support.

http://www.basicdatepicker.com/BDPLite/

Alternatively you can use the javacript below to open a new window
specifying the window size and removing the toolbars, status bars etc.

window.open('pagename.htm",'windowname','width=800,height=600,status=no,resizable=no,toolbar=no,scroll=no')

for further reference see the link below:

http://www.devguru.com/technologies/javascript/10894.asp

I recommend you The DHTML Calendar.

www.dynarch.com/projects/calendar

I use this control in all my web sites projects, its very usefull and
easy to configure.