THere usually is something called a "wand" tool (used to be activated by the hotkey "w", duh!). You can set different sensibility levels for that, depending on how good the contrast from the figure to the backdrop is - I usually use between 30 and 50 percent.
You select the tool, set the sensibility, and click on the white background - it should select all pixels within 50% colour variance from the one you clicked. You can then delete this selection, and the layer beneath should become visible.
Alternatively, you can use the "magnetic lasso" tool to trace a mask around the figure, although with good contrast, the magic wand usually works just as well and is quicker. If using the magnetic lasso, though, you might need to invert the selection, otherwise you will delete the figure, not the surroundings (wand tool, right-click, click "invert"). That said, my Photoshop is from 2002, so the actual names for the functions might have changed.