Lightbulb Charlotte on Mint Street in the Southend District opened in late 2009 and appears to be active - the twitter feed shows more-recent updates than the website.
Cowork.us has opened its doors at Area 15, check out the site or come on down and visit.
According to a March 2010 Art Institutes magazine story on coworking (whose linking policy I may be violating here), the Charlotte Art League operates a shared studio space that may have some coworking characteristics.
The Charlotte Observer reprinted a Seattle Times article about coworking on November 21, 2010, but failed to link to any of the local spaces (unless that is in a related article or sidebar that didn't get shown online, as sometimes happens).
CLTJelly ad-hoc casual coworking sessions happened 2009-2010 but appear to be on hold.
There was discussion about coworking in Charlotte in August, 2008, on the Momville website.
(Collective Giant entry removed 11/22/10 by Raines Cohen as it appears to point to a taken-over shopping website, and no other points of contact were provided)