Observing the eclipse is fun and easy with a pinhole viewer that you can build at home. It is not safe to view the sun directly. If you want to observe the eclipse please use the pinhole viewer described here or equipment specifically designed for sun viewing. The direct sun can damage your eyes through sunglasses, film negatives, mylar balloons, and other filters. Never look at the sun through a telescope or binoculars.
If you want a bigger image you need a longer tube. I was able to take two cardboard tubes which nested just inside each other to double the length. I taped a paperclip to the inner tube so it couldn't slip all the way into the outer tube. Affix the aluminum foil to the outer tube and the paper viewer to the inner tube for best results. Start with the tubes nested, find the image of the sun, and then gently extend the outer tube keeping the image of the sun in view.
You can find much more information about eclipses at this NASA link: http://eclipse.gsfc.nasa.gov/eclipse.html