Where i can find information and photo samples of nikon, canon and others digital cameras?

I will be happy if you give me link

Go to http://www.dpreview.com/...eview.com/

You will find lots of information under the reviews and specifications buttons.

And for sample photos, just select the camera on flickr:

You may notice that the sample shots of most cameras are of similar quality - that's because the person behind the camera and the lens is much more important than the camera body.
When shots from more expensive cameras look better, then it's often because the person using it is more serious about photography - someone who just wants to take some snapshots every few weeks is less likely to own a $2500 5D or D700 than an enthusiast who spends every free minute with his camera. And guess which one of these two will get better photos than the other one with just about any camera.

First go to the manufacturer site where they have a gallery of the most exquisite pictures.

Then go to blogs, reviews and forums where you will find endless pictures in every category!

I think amazon.com is a good site to view photos. Just type in the camera you want to see and you'll be able to see sample photos taken by people who have bought the camera.