If you rely on your iPhone's recurring alarm at any point during the weekend, you may want to set it manually today. Other countries are reporting an iOS bug that causes alarms to go off incorrectly during the daylight savings time switch.
Arguments about daylight savings time's usefulness aside, it seems recurring alarms in iOS have some serious problems when the phone's clock automatically changes—in that the alarm doesn't. Thus, if you depend on a recurring iPhone alarm to wake you up in the morning (or remind you of anything else), it might go off an hour late tomorrow due to the DST switch at 2 AM.
This bug is supposed to be fixed in iOS 4.2, but since it doesn't look like that's going to get released in the next 12 hours, you'll have fix the problem manually. For the days surrounding the DST switch, Apple recommends setting the repeat interval on your alarms to "never", which will fix the problem. After November 7th, you can set your alarms to repeat again. Don't forget to spread the word, either!