Lets Tutorial

<s:TextInput width="250" id="urlInput" text="http://" />

<custom:ImageButton img="@Embed(../lib/b_cut.png)" over="@Embed(../lib/b_cut_over.png)" toolTip="Crop area" click="goCrop();" buttonMode="true" enabled="{urlInput.text!=}" />
<custom:ImageButton img="@Embed(../lib/b_screenshot.png)" over="@Embed(../lib/b_screenshot_over.png)" toolTip="Take screenshot" buttonMode="true" enabled="{urlInput.text!=}" />

<s:NavigatorContent id="crop">
<s:VGroup width="100%" height="100%" gap="0">
<mx:HBox backgroundColor="#999999" width="100%" height="24" verticalScrollPolicy="off" verticalAlign="middle" paddingLeft="2">
<s:Button label="Back" click="{stack.selectedChild = loadpage}" />
<s:Button label="Continue" enabled="false" />
<s:Label id="cropStatus" />
<s:Label text="{urlString}" />
</mx:HBox>
<mx:HTML width="100%" height="100%" id="cropHTML" />
</s:VGroup>
</s:NavigatorContent>

[Bindable]
private var urlString:String;

private function changeState():void {
if (stack.selectedChild == loadpage) {
contentBox.setStyle("horizontalAlign", "center");
urlInput.text = urlString;
cropHTML.htmlLoader.loadString("");
}
if (stack.selectedChild == crop) {
maximize();
contentBox.setStyle("horizontalAlign", "left");
cropHTML.htmlLoader.load(new URLRequest(urlString));
cropHTML.width = contentBox.width;
cropHTML.height = contentBox.height;
cropStatus.text = "Loading";
cropStatus.setStyle("color", "#ffff00");
cropHTML.addEventListener(Event.COMPLETE, onCropLoad);
}
}

private function onCropLoad(evt:Event):void {
cropStatus.text = "Loaded";
cropStatus.setStyle("color", "#ffffff");
}

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
                       xmlns:s="library://ns.adobe.com/flex/spark"
   xmlns:custom="*"
                       xmlns:mx="library://ns.adobe.com/flex/mx" showStatusBar="false"
   width="450" height="300" creationComplete="init();">
   
   
<fx:Declarations>
<mx:ArrayCollection id="headerTitles">
<fx:Object step="Step one:" description="load a web page." />
<fx:Object step="Step two:" description="set your export preferences." />
<fx:Object step="Step two:" description="select the area you wish to crop." />
<fx:Object step="Step three:" description="set your export preferences for the cropped image." />
<fx:Object step="Final step:" description="please wait while your images are being expored." />
</mx:ArrayCollection>
</fx:Declarations>

<fx:Style>
@namespace s "library://ns.adobe.com/flex/spark";
@namespace mx "library://ns.adobe.com/flex/mx";

.descriptionText{
fontSize: 24;
color: #fff;
}

#headStep{
fontSize: 30;
fontWeight: bold;
color: #ffffbb;
}

#headDesc{
fontSize: 30;
color: #ffffff;
}
</fx:Style>

<fx:Script>
<![CDATA[
import flash.events.Event;
import flash.filesystem.File;
import flash.net.URLRequest;
import mx.events.FlexNativeWindowBoundsEvent;

[Bindable]
private var urlString:String;

private function init():void {
addEventListener(FlexNativeWindowBoundsEvent.WINDOW_RESIZE, onResize);
}

private function doBrowse():void{
var file:File = new File();
file.addEventListener(Event.SELECT, browseSelect);
file.browseForOpen("Load a webpage");

function browseSelect(evt:Event):void {
urlInput.text = file.nativePath;
}
}

private function goCrop():void {
stack.selectedChild = crop;
urlString = urlInput.text;
}

private function changeState():void {
if (stack.selectedChild == loadpage) {
contentBox.setStyle("horizontalAlign", "center");
urlInput.text = urlString;
cropHTML.htmlLoader.loadString("");
}
if (stack.selectedChild == crop) {
maximize();
contentBox.setStyle("horizontalAlign", "left");
cropHTML.htmlLoader.load(new URLRequest(urlString));
cropHTML.width = contentBox.width;
cropHTML.height = contentBox.height;
cropStatus.text = "Loading";
cropStatus.setStyle("color", "#ffff00");
cropHTML.addEventListener(Event.COMPLETE, onCropLoad);
}
}

private function onCropLoad(evt:Event):void {
cropStatus.text = "Loaded";
cropStatus.setStyle("color", "#ffffff");
}

private function onResize(evt:Event):void {
if (stack.selectedChild == crop) {
cropHTML.width = contentBox.width;
cropHTML.height = contentBox.height;
}
}
]]>
</fx:Script>
   
<s:VGroup width="100%" height="100%" gap="0">
<mx:HBox backgroundColor="#333333" height="46" width="100%" paddingTop="10" paddingLeft="10">
<s:Label id="headStep" text="{headerTitles.getItemAt(stack.selectedIndex).step}" />
<s:Label id="headDesc" text="{headerTitles.getItemAt(stack.selectedIndex).description}" />
</mx:HBox>
<mx:Box backgroundColor="#666666" width="100%" height="100%" id="contentBox" horizontalAlign="center">
<mx:ViewStack id="stack" change="changeState();">
<s:NavigatorContent id="loadpage">
<s:VGroup width="100%" horizontalAlign="center" paddingTop="20">
<s:Label styleName="descriptionText">Enter the link to the page:</s:Label>
<s:HGroup>
<s:TextInput width="250" id="urlInput" text="http://" /><s:Button label="Browse local..." click="doBrowse();" />
</s:HGroup>
<s:HGroup>
<custom:ImageButton img="@Embed(../lib/b_cut.png)" over="@Embed(../lib/b_cut_over.png)" toolTip="Crop area" click="goCrop();" buttonMode="true" enabled="{urlInput.text!=}" />
<custom:ImageButton img="@Embed(../lib/b_screenshot.png)" over="@Embed(../lib/b_screenshot_over.png)" toolTip="Take screenshot" buttonMode="true" enabled="{urlInput.text!=}" />
</s:HGroup>
</s:VGroup>
</s:NavigatorContent>

<s:NavigatorContent id="screenshotsettings">

</s:NavigatorContent>

<s:NavigatorContent id="crop">
<s:VGroup width="100%" height="100%" gap="0">
<mx:HBox backgroundColor="#999999" width="100%" height="24" verticalScrollPolicy="off" verticalAlign="middle" paddingLeft="2">
<s:Button label="Back" click="{stack.selectedChild = loadpage}" />
<s:Button label="Continue" enabled="false" />
<s:Label id="cropStatus" />
<s:Label text="{urlString}" />
</mx:HBox>
<mx:HTML width="100%" height="100%" id="cropHTML" />
</s:VGroup>
</s:NavigatorContent>

<s:NavigatorContent id="cropsettings">

</s:NavigatorContent>

<s:NavigatorContent id="export">

</s:NavigatorContent>
</mx:ViewStack>
</mx:Box>
</s:VGroup>

</s:WindowedApplication>