Nikon D5000 and Olympus UZ 800?

Nikon D5000 is a 5X zoom and costs Rs. 37000/- whereas Olympus UZ 800 is a 30X zoom and cost Rs. 23000/-. Why such a contradiction? What's so special about Nikon D5000?

It's a dslr with a much bigger sensor.

The UZ800 is a compact camera with a tiny sensor (less than the size of your smallest fingernail).It has a non-removable zoom lens of mediocre quality and though it is a nice camera with a lot of fun features, it is not in the same league as the Nikon (or any SLR for that matter).
The Nikon D5000 is little more than an entry level digital single lens reflex, and it is not a 5x zoom - it can accept any one of about 80 different lenses and many other accessories - the one you saw fitted with a 5x zoom can take that lens off and replace it with a longer or shorter zoom, a prime lens, an astronomical telescope or a microscope.
The sensor is, compared with the UZ800, huge. This allows it to take beautiful, sharp, saturated, clear images in very poor light, record high definition movies (yes, the UZ can record movies - but a camera of this kind can make TV quality films).
The camera is far more versatile than this brief summary - in fact, the question should be, with cameras like the Nikon and Canon SLRs available under Rs40000, how can companies have the hide to ask more than R20000 for a camera like the UZ?

The Nikon D5000 is a DSLR and the Olympus UZ 800 is just a digital camera.

Olympus UZ 800:
more megapixels, smaller sensor
unremovable lens
just a digital camera
no hot shoe mount

Nikon D5000
DSLR camera
less megapixles.much bigger sensor
removable lens
hot shoe mount

A DLSR (Digital Single Lens reflex) lets light pass through the lens, bonuce off a reflex mirror (the sensor is behind it) and the light goes through a pentaprism into a viewfinder. The viewfinder allows you to see more accurately what you're taking a picture of. A digital camera lets the light hit the sensor directly and it shows up on the screen. You can also do this with a DSLR.

The Nikon D5000 lets you detatch the lens that comes with it. You can choose from many lenses, telephoto, macro, different lengths, different ƒ numbers. You can't take the Olympus UZ 800's lens off.

The megapixel myth is that more pixels means better picture-which is actually half true. Cramming lots of pixels onto a small sensor like on the Olympus UZ 800 means alot of image noise, while on a much bigger sensor on the D5000 means much clearer pictures but with less megapixels.

DSLR's like the D5000 allow for accessoires such as external flashes, battery grips, different lenses, uv filters, etc. Not like the Olympus UZ 800.

DLSR cameras are a completely different breed of digital camera.