In reply to woolsack:
My experience of wheel bearings going is that the hum rather than squeal. If there is no obvious signs of wear on the disks and no significant heat build up on the wheel compared to the other front wheel I wouldn't be too worried about it. Even if it were a front wheel bearing it's highly unlikely to fail catastrophically as they are designed to fail safe and you'd know all about it long before it did and the wheel would be flopping around all over the shop.