USA timezone in AS3

//out of DST
var a:Date = new Date(2010, 1, 1);

//in DST
var b:Date = new Date(2010, 7, 1);

var observesDST:Boolean = true;

if (a.timezoneOffset == b.timezoneOffset)
{
	observesDST = false;
}

var timezone:String = "ET";//Default to Eastern
switch (a.timezoneOffset / 60)
{
	case 10:
		timezone = "HI"; //Hawaii
		break;

	case 9:
		timezone = "AK"; //Alaska
		break;

	case 8:
		timezone = "PT";//Pacific
		break;

	case 7:
		timezone = "MT";//Mountain
		break;

	case 6:
		timezone = "CT";//Central
		break;
}

if (timezone == "MT" && !observesDST)
{
	timezone = "AZ";//Arizona
}

trace(timezone);