U can work anywhere u like. It really does not matter. I am also in my opt. But at the time of filing H-1b U must have got a decent job right know u can work in gas station, subways anywhere but at h-1 B filing u need a good sponsor and that can be any US company and the job u are doing should be related to your major. So dont worry right now but by he time of April better get a desent job or go to consultancy...