Strange noise
 

When ever I push the back out of the garage I get a noise coming from the front of my bike. It sounds as if it is the front mudguard rubbing on something or flexing.
It could be the discs rubbing slightly on the pads I suppose. I'm not particulary worried about it but it annoys the hell out of me everytime I move the bike.
Anybody got any ideas, from my limited discription?