can some body plz help me ,which is the best model to shot log distance photos?

i would like to tack pictures from long distance like mountains , so what i need to concentrate like mega pix or zoom ?

In this case, both megapixels and zoom are important for different reasons. Let me break it down:

Megapixels are often used sort of unscrupulously by advertisers to hook consumers. While it's true in general that more megapixels is better, they aren't the end-all-be-all of digital photography. First of all, in recent model years many manufacturers have turned to a practice called "pixel cramming." This means that when they release a new model, they simply force more pixels onto the same size sensor chip, which results in higher digital "noise" in the pictures. However, the right resolution paired with a correctly-sized chip will of course result in beautiful pictures. The principal advantage of higher-megapixel cameras is the ability to make large prints of photos while retaining fine detail, and this is crucial for the kind of landscape photography you're talking about.

I think that zoom is more important than megapixels here, though. Mega-zoom cameras (generally 10x optical or greater) truly allow you to get up close and capture that detail that the megapixels will eventually record. You want to make sure that you stay away from digital zoom, as it will distort your pictures far more badly than any pixel cramming ever could. Look for cameras with large optical zooms paired with quality lenses. Additionally, many manufacturers offer cameras with stabilized zooms, meaning they compensate for your hands shaking or other environmental issues in order to produce a sharper image. I myself own a Canon Powershot S2 IS, which features this kind of technology, and I can tell you that it works spectacularly well.

I'm going to assume that you're not interested in going pro with a digital SLR. Outside of the pro realm, there are really three main options for high-MP, stabilized long zoom:

the Canon S line (S2 IS, S3 IS)
the Panasonic FZ line (FZ4, FZ5, FZ30, FZ50)
the Sony H line (H2, H5)

All of these cameras have their minor pluses and minuses, but in truth they're all fine machines and all of them would suit your purpose. These are all semi-bulky, SLR-like cameras. You haven't stated here whether you have a preference as to size, but there are also smaller cameras that have similar megapixel and zoom ratings. The reduction in size usually comes at the cost of a reduction in features (fine control over camera settings, etc). Some of these smaller cameras include the Nikon Coolpix S10 and the Panasonic Lumix TZ1.