(T) Grinding from front right

OK, my Bravo 1.6sx (2000) has started making a repetitive grinding noise. As I go faster, the grinding gets faster too, so I guess its got something to do with the wheels rotating. It sounds almost like the brake pads are rubbing with one part of the disk so as the wheels turn faster the noise is slightly higher pitched and closer together. It sounds like its coming from the front drivers side. Do any of you mechanically minded types have any ideas what could be the cause? I guess I'll end up taking it to the garage, but I'd rather have some idea first so I don't get quite so ripped off.

time to replace brake pads, and probably discs too coz you've waited too long.
then again it could be the wheel bearing. does it get louder when turning one way and quieter when turning the other?

Thanks for the reply! I thought that, but we had new pads AND disks a year ago, and they still look in pretty good shape. It sounds a little different to how the worn pads sounded too - more of a hum than a metal on metal grinding. Any more suggestions welcome!

A humming sound suggests a bearing.
Another possibility is that a brake is slightly binding. When slackening your grip does the car veer towards the left or right at all. Remembering that the roads are cambered.