The Wish List by Eoin Colfer
Meg Finn is in trouble, unearthly trouble. Cast out of her own home by her stepfather after her mother's death, Meg is a wanderer, a troublemaker. After a botched attempt to rob a pensioner's flat, Meg and her partner in crime, Belch, end up in a very sticky situation. Meg's soul is up for grabs as the divine and the demonic try every underhand ploy imaginable to claim it. Her only chance of salvation is the Wish List. But how can she persuade the pensioner Lowrie to help her when she has wronged him? Even if she can persuade him, will she really have enough points to face up to St Peter?