This is interesting. Engadget has a screenshot of the UK Apple Store that shows iOS 4.1 scheduled to be released on Wednesday, September 8th.
The US Website still shows the usual “Coming Soon” announcement so we’ll go out on a limb here and say that the 8th is the day. Any ideas on how this inconsistency of information happens?
As usual when a new firmware comes out, make sure not to “accidentally” upgrade if you want to keep your jailbreak and unlock.