I believe the real question is carefully concealed in this phrase:

based on the date how do I get the day of the week and display it.

That is, when the user asks to start the calendar at January 3, 2005, how do you know what day of th eweek that falls on so as to correctly format your calendar?

You need the Perl moduleDATE::CALC

which has the functions:

#returns the week number of the date input
$week = Week_of_Year($year,$month,$day); 
#returns the date of the monday of the week input
($year,$month,$day) = Monday_of_Week($week,$year);
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So you can do, (pseudo code):

- get $begin_day, $begin_month, $begin_year and $end_day, $end_month, 
+$end_year  from form input

$begin_week = Week_of_Year($begin_year,$begin_month,$begin_day); 
($begin_year,$begin_month,$begin_monday) = Monday_of_Week($begin_week,
+$begin_year); 

$end_week = Week_of_Year($end_year,$end_month,$end_day); 
($end_year,$end_month,$end_monday) = Monday_of_Week($end_week,$end_yea
+r); 

#note that in above month and year get changed in case the range strad
+dles months or years

- calculate $number_of_weeks in range either using a Date::Calc functi
+on or $end_week - $begin week

$monday_date = $begin_monday;
for $w (1 .. $number_of_weeks) {
     print days-of-week row;
     print dates row starting at $monday_date
     for $r (1 .. $number_of_rooms) {
          get room data and print it;
     }
$monday_date = $monday_date +7;
}
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