<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/08/25/changing-a-checkbox-controls-label-placement/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:ApplicationControlBar dock="true">
        <mx:Label text="labelPlacement:" />
        <mx:ComboBox id="labelPlace" selectedIndex="1">
            <mx:dataProvider>
                <mx:String>{mx.controls.ButtonLabelPlacement.LEFT}</mx:String>
                <mx:String>{mx.controls.ButtonLabelPlacement.RIGHT}</mx:String>
                <mx:String>{mx.controls.ButtonLabelPlacement.TOP}</mx:String>
                <mx:String>{mx.controls.ButtonLabelPlacement.BOTTOM}</mx:String>
            </mx:dataProvider>
        </mx:ComboBox>
    </mx:ApplicationControlBar>

    <mx:CheckBox label="Label"
            labelPlacement="{labelPlace.selectedItem}" />

</mx:Application>