UPDATED: I updated the templates and added a 3rd template. Now a 5 column email template with 10/15px gutters. .png and .psd file formats. Please download them here.
UPDATED: I have created a 3 column in addition to the 8 column layout. Now in Fireworks .PNG File also.
I am sure there are more elaborate email templates out there. I just wanted to share what I made and use to start my email designs. It is a .PSD file. 600pxels wide - 8 Columns with 10/20 px padding in-between columns with guide.