There are two ways to set the initial date of the calendar
The first is to the use the "initialDate" property. This property controls what date is displayed when the calendar first comes up. The default value is the current date. But you can set it to any valid date value. You would set the property like the code below, using a vaild javascript date value.
objCal.initialDate = new Date(2009, 10, 1);
The second way is using the scDate querystring parameter. You've already toched on how to do it, and you've asked me for a specific example...
<!-- scriptcalendar iframe tag -->
<iframe id="scIFrame" name="[license key]" src="scthemes/standard/scrptcal.htm?scDate=10/1/2009" scrolling="no" frameborder="0" width="800" height="700" >
</iframe>
But, the forward slash should really be URL encoded, so use this instead...
<!-- scriptcalendar iframe tag -->
<iframe id="scIFrame" name="[license key]" src="scthemes/standard/scrptcal.htm?scDate=10%2F1%2F2009" scrolling="no" frameborder="0" width="800" height="700" >
</iframe>