So, it seems that Apple can't get even timezones right. In 2010. I have an iPhone 4. I've had an alert at 7 am. It worked fine in the summer. Today, not so great. Fortunately I wake up before the alert, otherwise I'd woken up at 8 am.
I deleted the alert, created a new one, just maybe it's just a problem with old alerts. No such luck. The new one alerts also an hour later. And at least one other user has reported the same today.
Come on, Apple. You're really going to have bugs like this? Shame on you.
Also, iOS 4.1 has a bug in calendar which forces me to go to the day view and then back to the list (which I prefer). Otherwise the whole list is empty. This did not happen in 4.0 or 3.x.