ColdFusion's built in function getTimeZoneInfo() doesn't allow you to pass a date. It give you the server timezone info and offset as of "now" (as in, when the code is run).
If you need to find the timezone offset for a specific date, you can use the TimeZone class from java. Here is the code.
<cfset myDate = "11/01/09" /> <cfset timeZone = createObject("java","java.util.TimeZone") /> <cfset myTimeZone = timeZone.getTimeZone("America/New_York") /> <cfset myTimeZoneOffset = myTimeZone.getOffset(1,year(myDate),month(myDate),day(myDate),dayOfWeek(myDate),0) />