Disc brakes sound

[Catrin]

There is something odd with my Jamis, and I don't know enough about disc brakes to know if this indicates a problem...

This doesn't happen when I am riding or braking, it happens only when the bike is still and I am holding it while unlocking my door, something like that. The fork moves a little and there is a very high pitched metallic squeel. It isn't loud, but VERY high pitched. I doubt they could hear it at the LBS because there is so many other sounds that would likely mask it.

Oddly enough the sound continues for a few seconds after I stop the bike from moving - and it only happens when the fork makes very slight movements - typically when I've tipped the bike sideways rather than forward movement. Once I actually roll the bike forward for real movement it doesn't happen.

I hope this description makes sense, it is difficult to describe. Any thoughts on what might cause this? I am tempted to ignore it, but I don't know enough about discs to know if this is wise...