Just got an email from Elon:
The static fire took place on Saturday [20 Sep 2008, CA time], as expected, and no major issues came up. However, after a detailed analysis of data, we decided to replace a component in the 2nd stage engine LOX supply line. There is a good chance we would be ok flying as is, but we are being extremely cautious.
This adds a few extra days to the schedule, so the updated launch window estimate is now Sept 28th through Oct 1st [CA time].
So if they hold to that schedule, the fourth Falcon 1 launch attempt could be early next week.
This may be a good example of one way in which privately run space programs can outdo government ones. The engineers and technicians working on the Falcon 1 were able to get a lot out of the three prior launch attempts and press on to the fourth. If this was a government program, the program already would have been shut down and we’d have lots of finger pointing and investigations to determine what went wrong and who was going to get the axe. As it is, they don’t have to do successful public spectacle and keep politicians happy–they just need to be making real progress and keeping the (presumably intelligent) investors satisfied. Also unlike a government program: if this fails to work after a while, the whole thing will just get shut down.