First I started at the International Society for Arachnology page. The web was kind of orb-ish, so I clicked on the Orb web spiders page. Lo and behold, there was a picture of the spider, Argiope aurantia. This spider apparently goes by several aliases: Yellow Garden Spider, Black-And-Yellow Argiope, Golden Orb Weaver, Yellow Argiope, Writing Spider, Golden Garden Spider. According to this page, the spider should be mostly harmless. Sure doesn't look it.
So there you are. Yet another illustration of the power of the Internet :).