Well it will be short - for Gregorian calendar it will be:

public static function resolveEasterDate(year:Number):Date {
	var a:Number, b:Number, c:Number, 
	d:Number, e:Number, f:Number, g:Number, 
	h:Number, i:Number, k:Number, 
	l:Number, m:Number, p:Number;
	a = year % 19;
	b = int(year / 100);
	c = year % 100;
	d = int(b / 4);
	e = b % 4;
	f = int((b+8)/25);
	g = int((b-f+1)/3);
	h = (19*a+b-d-g+15) % 30;
	i = int(c / 4);
	k = c % 4;
	l = (32+(2*e)+(2*i)-h-k) % 7;
	m = int((a+(11*h)+(22*l))/451);
	p = (h+l-(7*m)+114) % 31;  
	return new Date(year,int((h+l-(7*m)+114)/31)-1, p+1 );
}