No mate, is a feature that has not been added, strange though as it s common with all other OS. Hopefully they will add it soon. I use my phone as my alarm and I need to make sure its on the top ring volume, otherwise god himself wouldnt be able to wake me, which is obviously not helpful when listening to music before i fall asleep. You would think it would be quite easy to implement and I have voted for it to be in the Microsoft suggestion box.
While I am on the subject another missing feature, which I have also voted to be implemented and which I have seen added in some apps settings, the bbc mobile third party app springs to mind, but not on the general phones setting is the ability to lock the screen orientation. I like reading websites vertically and playing games watching videos in the horizontal aspect. I absolutely hate it when the phone flips and I have to jiggle it to get the orientation back to the way I like it. If some apps can implement the lock orientation I am not sure why it can't easily be added to the OS, or some third party appster ;) hint hint. Heres hoping.
That said I am loving my windows phone, bored of the boring IOS and as an early adopter I am hoping new features will be implemented as time goes on.