I'd say go to cwtv's website. Looks to me like Supernatural is alive and well. I'm showing this show alive and well with new episoded effective from May 2010. If in doubt, I'd say do a quick search on an engine like Google.
As of June 2010, the show was renewed for a sixth season. It will begin airing again in the fall, on the WB network, Friday evenings at 9PM. The fifth season concluded on May 13, 2010.
