MacBook Pros with nVidia graphics cards are great for gaming but the power hungry graphics cards drain your battery when not in use. gfxCardStatus allows you to choose the which chipset you want to remain active so that you can extend battery life and maximize power manually.
gfxCardStatus places a small icon in the menu bar and displays a small n for nVidia or i for the currently active Intel graphics chip set. Just use your mouse to switch manually between the two when needed. If you disable the nVidia card permanently, you will should notice an increase in your battery life.
It's a shame gfxCardStatus doesn't detect automatically when to activate your nVidia graphics card but nevertheless, it gives you the possibility to extend your battery life manually.