I have a gtx 570 and I'm interested in undervolting. How would I go about undertaking such an endeavour?
Use Afterburn, it will let you undervolt your GPU.
NOTE: I have tried that on my card (See sig) and it is not advisable, because FPS will drop considerably.
EDIT: Ok, if you want to make a non gaming profile than it's a different story all together. Here you can create a power saving profile using Afterburn, where you can undervolt the GPU considerably and also downclock your GPU, this profile is safe to use for watching movies and other 2 D tasks. Also you can create a auto fan profile which can help further to keep the temps down.
Hope this helps.