I have a 2003 SSEi and just noticed, when the window is down, that there is a constant squeelilng noise when moving - but it stops as soon as I hit the brakes (and comes back when the brakes are released). Any thoughts on what this could be?

Thanks!

sounds like you are going to need brakes those may be the squealers on the pads

Yep, sounds like the tattle tail tabs. They rub on the rotor when the pads get low to remind you to change the brakes.

You know, I was thinking that - but talked myself out of it because I convinced myself that those tabs only hit the rotor and squeeled when the brakes were applied.
Rethinking it: They make the wear sensors closer to the rotor so when the pad gets to that point (not much pad left) - it will squeel to let you know - and when the brakes are applied, it will stop because the pads will then grip the rotor.
Anyway, thanks for the help and for fixing my confused brain.

Any time. That'* why we're here.