Will sigma 17-50mm f2.8 ex dc os hsm work on a full frame camera?

Thinking of buying the sigma 17-50mm f2.8 ex dc os hsm for my nikon d3100 which is a dx camera.
The thing is i will upgrade in a full frame dslr in 1-2 years so i don't won't to be buying a lens that won't be usefull on my future full frame camera
will those lens be ok? I'm bying the hsm version so would be able to autofocus on nikon d3100

Nope, this is a crop frame lens. Even if you were able to mount it on a full frame camera, there would be alot of vignetting around the four corners of the frame.

If you are planning to go full frame then I would suggest getting one these lenses. They have the same range as 17-50 on a crop frame.

Sigma AF 24-70mm f/2.8 EX DG HSM
http://www.amazon.com/...001NEK2QO/

The Nikkor 24-70 2.8 is very expensive, about 1800 bucks.

The "DC" tells you that it is designed for cameras with a APS-C sensor, so no it is not designed for your full frame camera, however any Nikon full frame camera can used it. The camera will automatically crop the sensor to give you a full 3:2 aspect ratio of an APS-S sensor.

If you buy any of the Sigma "DG" lenses they will give you a full frame view when you do upgrade to a Nikon D600, D800, D4 or any of the Nikon full frame cameras

This is a great lens - I have one. All good lenses have resale value, so if you think you will want to use one over the next couple of years, you will get your money back at resale time.