[NSDate date]in iOS 4.0 used to return date in the format: 2010-09-15 09:28:26 +0530
but now in iOS 4.1 it returns the date in the format: 2010-09-15 09:28:26 GMT
In iOS2.x and 3.x the NSDate description/datefromstring function returns: 2010-09-24 17:30:00 - 0700
in iOS 4.1 it returns this: 2010-09-25 00:30:00 GMT
You could submit a bug to apple.