I'm reading 'The Scatterlings' by Isobelle Carmody.
its just a SF book I picked up in an Oxfam shop, for taking on holiday, that I never got round to reading.
Its about a girl who wakes up in a wrecked police flyer, with no memory of who she is, on a planet with a two tier society, i.e. an underclass, whom she meets after finding it was their sabotage that crashed the flyer.....
she also keeps hearing 'voices' in her head - thats the first 50 pages, its been quite good, so far.