not sure if this is real or not. but if its like clip board on windows, its just a place where data is stored temporarily until you transfer (paste) it somewhere else. but then again, i dont have a fascinate
If its the same as the droid 2 then you long press in a text field and select paste from clipboard. The last 15 or so things you copied will be stored there. I don't think there is any tangible way to access it though.