Rear Wheel Noise (Euro '07)

Recently, when I start the car, put it in drive or reverse and slowly let the brake off, there is a distinct high pitched buzzing noise coming from, what sounds like, the drivers side rear wheel (could be both sides though). It lasts for around 8-10 seconds, or until you get some speed up, then goes away and won't come back unless you turn the car off, let everything cool down, and on again.
Not sure if its related, but sometimes while driving there is this high pitched squeal coming from the same area - sort of like something is rubbing on a disc. It will last for around 8-10 seconds also, but I can't replicate this noise.
Checked pads - fine, checked all components in the area - secure, no visual evidence of what might be causing the noise.
Current thoughts: ABS??
http://vimeo.com/75371925

Worn rear brake pads.
All sorted.