Full code after the jump.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/04/14/calling-a-simple-web-service-from-flex-using-the-webservice-class/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            import mx.controls.Alert;
            import mx.rpc.events.ResultEvent;
            import mx.rpc.events.FaultEvent;
            import mx.utils.ObjectUtil;

            private var startTime:int;
            private var endTime:int;

            private function button_click():void {
                webService.getMonths.send();
                startTime = getTimer();
                lbl.text = "";
            }

            private function getMonths_result(evt:ResultEvent):void {
                textArea.text = ObjectUtil.toString(evt.result);
                calcTime();
            }

            private function getMonths_fault(evt:FaultEvent):void {
                Alert.show(evt.type);
                calcTime();
            }

            private function calcTime():void {
                endTime = getTimer();
                lbl.text = "total time: " + (endTime - startTime) + "ms";
            }
        ]]>
    </mx:Script>

    <mx:WebService id="webService"
            wsdl="http://www.flash-mx.com/ws/months.cfc?wsdl">
        <mx:operation name="getMonths"
                resultFormat="object"
                result="getMonths_result(event);"
                fault="getMonths_fault(event);" />
    </mx:WebService>

    <mx:ApplicationControlBar dock="true">
        <mx:Button id="button"
                label="get months from web service"
                click="button_click();" />
        <mx:Spacer width="100%" />
        <mx:Label id="lbl" />
    </mx:ApplicationControlBar>

    <mx:TextArea id="textArea"
            editable="false"
            width="100%"
            height="100%" />

</mx:Application>

View source is enabled in the following example.

If you’re using ColdFusion, the months web service is as follows:

months.cfc

<cfcomponent output="false">

    <cffunction name="getMonths" access="remote" returntype="array" output="false">
        <cfset var monthNames = ListToArray("January,February,March,April,May,June,July,August,September,October,November,December") />
        <cfreturn monthNames />
    </cffunction>

</cfcomponent>