If you are looking to see a gauss gun being used as a weapon, your best bet is too run out and buy some futuristic video game. At this point in time, there are no known (unclassified?) portable weapons that fire with electromagnetic forces. However, some prototype, tabletop sized models have been built, and below you can find some links to see some current experiments in Gauss Gun technology.
Sam Barros's POWERLABS currently has built a nice single stage Gauss Gun and there are also developing a powerful multi-stage gun.
POWERLABS 2600-Joule Multi Stage GaussGun.
EnergyBeam.com has developed a gauss gun can crusher.
http://www.energybeam.com/energybeam.com/can-crusher.html
The University of Texas has a nice Rail gun and Gauss Gun