http://flex.actionscript.it/index.php?title=RssPanel_En
You will be asked to give a name to the new plugin, e.g. FlexRssReader, this will be the name Eclipse will show you when you in the menu. In the bottom field insert the following address: http://flex.actionscript.it/plugins/RssFlex/ or http://flex.actionscript.it/plugins/RssCss/