craftgrrl | help for enlarging a stencil?

I want to make a political banner on a large piece of cloth (probably a long strip of cheap cotton muslin). My plan is to spray paint the text by hand, but I really want to use a stencil image of the President's face. I've found a couple of great stencils online that will let me print them out and use them for free, but I'm not sure I can easily print something out that's going to be about a yard tall and about the same width. Any suggestions on ways I can enlarge the image for my banner that don't involve using the giant printer at Kinkos? Is it possible to print a very large image on multiple pieces of paper without trying to cut the image by hand in the image program? I have access to Photoshop.

Thanks for any help you can offer.