I just checked a couple of NOAA radar links on my site, and came up with the same site via both links, one of which used to be a clickable US Radar Map. They both now pointed to the US Radar Sites,
http://radar.weather.gov. The old clickable map is now broken and probably dying at
http://www.nws.noaa.gov/radar_tab.php. Meanwhile they have now set up a National Mosaic with Threats page that incorporates a GoogleMaps layer and ajax,
http://www.srh.noaa.gov/ridge2/ridgenew2/, on which they're inviting comments until Oct. 2012. The new page is interesting.
What has everybody else found?