This another one of those little gems i've found browsing the internet that I just had to share. gfxCardStatus is a simple application that runs in the background and gives you full control over the graphics in your Macbook Pro. In the System Prefs of your mac you only have 2 options to choose from, Full Time Discrete or Dynamic Switching. With the implementation of gfxCardStatus you have a third option, Integrated Only. Being able to designate which card to use on the fly has actually been incredibly useful for me. When i'm in class the Integrated Only option gets me through my 6-9 with battery to spare.
If you need the extra battery life or just want more control over you Graphics Cards, this is the application for you.
The application can be downloaded for free here - http://codykrieger.com/gfxCardStatus