I have played around with accessing satellite imagery, including the data provided by Landsat-7. They do both commercial and government imagery. They told me it gets down to about .4 meter resolution, but US law forbids them from selling anything lower than .5 meter resolution. The higher-resolution stuff is for government use only, and you could definitely see some pretty interesting things if you had access to a satellite like that. That is quite scary.

Think of how many terrorists he stopped though!