To everyone with IOS6 Sound related issues & Others
If you are facing a problem of not having any system sounds, notification sounds, no calls or other software sound related issues I'd suggest you read below it's a stupidly simple fix and it should solve most software issues after an immediate iOS6 update:
After updating unplug the phone from your computer and leave the phone alone for 5-10 minutes, if you still have problems: reboot, wait a few minutes and all sound related problems should be fixed.
When I updated to iOS 6 I had lost my system sounds, so I unplugged from the computer, rebooted the phone and still no go. I decided to just let the system "settle in" for a bit, let it lock and when I unlocked after 5-10 minutes sounds were back and everythings up and running again.