From http://www.spaceweather.com/ , where you can get a sky map and pretty comet photos--
Only a few days ago you needed a telescope to see Comet Swan. Not anymore. The comet has suddenly brightened to naked eye visibility. The cause of the outburst: Probably, a crack has opened in the comet's nucleus, exposing a fresh vein of volatile ice to vaporizing sunlight.
To see the comet, go outside after sunset and look west. It is about halfway up the sky gliding through the constellation Corona Borealis. To the unaided eye it looks like a faint, fuzzy star. For full effect, look through binoculars or a small telescope. Swan's huge green atmosphere and long sinuous tail are beautiful.