The satellites for which there is publically available info** are definitely incapable of resolutions supporting reading written text or even car license plates; nor distinguish facial features.
The best ones are supposed to be Keyhole-class KH-7 (2.5") followed by KH-11 (4-6").
First off, some results from http://hypertextbook.com/facts/2001/JeannelleLouis.shtml
(Resolution of a Spy Satellite, The Physics Factbook™; Edited by Glenn Elert -- Written by his students)
Source: Massive New Top Secret Spy-Satellite Program to Cost up to $25 Billion. Los Angeles Times. 7 June 2001.
Data: Approximately 6 inches on current satellites
Source: Satellites System Overview Articles. America Online: Path: Spy Satellites.
Data: Type KH-11 Spy Satellites, 10 cm/4 inch resolution; KH-7 -1966 2" Resolution.
Source: Silber, Kenneth. Spy Satellites: Still a Few Steps Ahead. 21 September 1999.
Data: According to an estimate by the private Federation of American Scientists (FAS), three satellites operated by the US National Reconnaissance Office (NRO) have resolutions as sharp as 10 centimeters (3.93 inches) -- in other words, the satellites can discern a softball-sized object from several hundred miles away."
Three are “visible light” satellites, the most recent of which resemble the Hubble Space Telescope and were built by the same contractor at the same Lockheed Martin facility in Sunnyvale, Calif. They are known in the spy trade as “Keyhole-class” satellites. And they have a resolution of 5 to 6 inches, meaning they can distinguish an object that small, but no smaller, on the ground.
Two other satellites are radar-imaging, built by Lockheed Martin in Watertown, Colo. Their resolution is about 3 feet.
While satellites cannot read license plates, they can tell if a car has one. While they cannot tell a mullah by the length of his beard, they can help analysts figure out how many people are chanting along with him at a street demonstration. And while they cannot hover over an area and provide real-time images, other “assets” such as unmanned aerial vehicles, also known as drones, can do that.
Please note that in addition to classified proprietary tech, the modern movenet is towards using commercial capabilities.
The bulk of the article talks about cancellation of Boeing's Future Imagery Architecture (FIA) program. The rest covers what replaced it:
U.S. commercial satellites now have better than two-foot resolution, meaning each pixel in a digital image spans 24 inches. In April, a satellite will be launched with 16-inch resolution. By 2011, that is expected to narrow to nearly 10 inches. Tighter resolutions let analysts see details that allow them to accurately identify missiles and other targets.
As a GeoEye spokesman noted today, his company has already committed more than $30 million dollars to the next generation satellite, known as GeoEye 2, and ITT is already grinding its 1.1 meter mirror.
Ground resolution for pictures taken from this satellite would be a remarkable 9.75 inches.
In addition, from the Washington Post article ("A LOOK AT Spy Satellites & Hollywood" By Dwayne A. Day); now saved at http://www.c4i.org/spysats.html
(Dwayne Day is a space policy analyst and historian who lives in Northern Virginia. He is the editor of "Eye in the Sky" (Smithsonian Institution Press), a book about early spy satellites.)
Even if a satellite had the right angle on the license plate, it wouldn't be able to make out the letters and numbers. The best resolution of an American spy satellite, achieved by an older series no longer in use, was reputed to be about 2 1/2 inches. This means that the smallest visible object would be the size of a baseball, not the thin letters and numbers on a license plate. And smoke, haze, smog or clouds would all reduce the quality of the resolution, as would the distance required to see the license plate from an angle. Memo to future filmmakers: License plates cannot be read from satellites.
I presume he meant KH-7.