Hey ArcIMS users....

You can use an ArcIMS datasource as a basemap, as follows:

<?xml version="1.0" encoding="utf-8"?>
<mx:Application
xmlns:mx="http://www.adobe.com/2006/mxml"
xmlns:framework="com.esri.aws.osgi.framework.*"
xmlns:map="com.esri.aws.awx.map.*"
xmlns:layers="com.esri.aws.awx.map.layers.*"
layout="absolute"
>
<framework:Framework apiKey="19640523"/>
<map:Map>
 <map:basemaps>
  <layers:ArcIMSGroupLayer id="world"
   serviceHost="http://www.geographynetwork.com"
   serviceName="ESRI_World"
   />
 </map:basemaps>
</map:Map>
</mx:Application>

Don't forget to place a crossdomain.xml file at the base of your ArcIMS host. Check out the Geography Network cross domain file as a sample.