Hi,
Yep, poor timing with the downtime. Terraserver, however, is still up and running just fine. So you should be able to get topo and aerial tiles.
Try this: open up TF, and switch to one of the Topo tilesets. You may still get an error message about the server being down. But that's because it was trying to download landsat tiles.
Now close TF and open it back up. As long as you stay in a topo or aerial tileset, you shouldn't get any messages about the server being down.
Hoping to get an update about the server's status soon.