Since updating to Jelly Bean, I can no longer change the settings of my alarms on my S3 i.e snooze (time in between, length), activate smart alarm, change the alarm tone etc... When I click more, it just lets me change the volume. Can anyone help?
I'm not sure, but since you updated to JB, It may have other stock alarm app, so it wouldn't be some bug. Although you can download an app for this, like Xtreme Alarm which is free.
Or you can search on XDA forums the stock alarm APK for ICS. I've found this topic, which lists a lot of stock apps for downloading.