For many years Microsoft provided a WMS that included USGS topos and US aerial photography. Popularly known as TerraServer (or Microsoft Research Maps -MSRMaps), the service no longer exists as of 5/1/2012, meaning that the Google Maps mash-up I created using the data no longer work. For more info on TerraServer’s death check out the post on Directions Magazine’s All Points blog.
No worries from my end, as the use of that pages was nearly non-existent! People are way more interested in my OpenLayers Google Mash-Up 
. I’ll update my links accordingly, again, not that it matters because people weren’t interested in Microsoft’s WMS service. Thankfully today there are many, many more options for streaming high quality basemap data through web mapping applications.
Yes I guess Dr Jim Gray isn’t remembered much anymore. But, note that the quad tile pyramid originated with Dr Gray and TerraServer so GMaps owes a passing thought to Jim.
I’ve read elsewhere about the end of msrmaps, but I just now accessed maps from
http://msrmaps.com/ogccapabilities.ashx
using our application. It seems that it’s still working at least temporarily.
Bruce, thanks for the info! It does appear that the service is available (and my mash-ups that use them work). But, let’s see for how long!