For good discussions of POV try these links:
PROS and CONS of Writing in Omniscient Point of View
They're Just Techniques, People! Observations about flipping viewpoints
The following is an exercise I did for a writing course. It is the opening paragraph(s) of a short story I wrote, "Happily Ever After." The first sample is one of my earlier drafts, which I wrote in first person, present tense. Then I retooled it to play with third person limited and omniscient points of view. I had a lot of fun with it as I saw the different effects the choice of POV can make on the mood and atmosphere of a piece.
POINTS OF VIEW
The sun is shining, although I can’t see it. Thin rays of light penetrate through the cracks of tightly-nailed shutters, painting stripes on the rough floor boards of my attic room. Dust motes dance drunkenly in the beams, and I don’t like it. When the morning dance starts, they come. I don’t like the dark, either, but at least they leave me alone then, my single candle burning, burning, burning, until it gutters in a pool of molten wax.
The dust motes dance faster and they come. The man with the paper and the ink. The woman with the tray of porridge, tea, and hot water. The cat with the blank, unwavering stare.
Third person limited
Thin rays of light crept through cracks in the tightly-nailed shutters and fell across Eddi’s face. She stirred and opened reluctant eyes. She hated the morning sunbeams that ushered her into another day. If only she could stay asleep, not having to face the man, the woman, and the cat. Heaving herself up off her bundle of blankets, she stretched, her muscles protesting the movement. She sat down at the table and they came: the woman bringing her breakfast, the man thrusting more paper and ink at her, and the cat staring knowingly at her.
Third person omniscient
The girl sleeping on the pile of blankets in the dusty attic stirred as the morning sun sent thin rays of light across the room. For some, a new day heralds new challenges, new adventures, but for Eddi, it just meant being nothing but trash. She got up and shuffled to the window and tried to block the sunbeam that shone through the cracks of the tightly-nailed shutters. She’d welcome the sun if she were allowed to see it, if the morning didn’t bring the man thumping paper and ink on the table, the woman bringing the cold, lumpy porridge, and the cat. That cat watching the dust motes dance.
Another attempt at omniscient
It’s too bad, really. The girl sleeping on the heap of blankets looks almost—well, not peaceful, not happy, but—relaxed. Yes, relaxed. She never looks that way when awake. And why not? It is in sleep when she can escape the prison of the attic room, the demands of the man, the accusations of the woman, and the disdain of the cat. Sleep—the girl’s only refuge—soon to be torn from her by the inexorable sunbeams penetrating the cracks in the old wooden shutters and creeping, creeping across the floor. The light sweeps across her face and she stirs, grips the frayed edge of the blanket, and mumbles a protest, even as footsteps ascending the stairs can be heard through the locked door that keeps her in but not them out. Too bad. Too, too bad.
My final draft (if there ever is such a thing)
Thin rays of light penetrate cracks in the shutters, painting stripes on the rough floorboards of my attic room. Dust motes dance drunkenly in the beams, and I don’t like it. When the morning dance starts, they come. I don’t like the dark, either, but they leave me alone then, my single candle burning, burning, burning until it gutters in a pool of molten wax.
The dust motes dance faster and they come: the man with the paper and the ink, the woman with the tray of porridge, tea, and hot water, the cat with the blank, unwavering stare.