In the Upstate, there are places where roundabouts have been designed with bicyclists in mind using a variety of standard practices. Here's a photo of a roundabout in Greenville, South Carolina (near Woodruff Road, on Carolina Point Parkway). There are several signs to help a variety of users navigate the facility.
Being a part of APBP (that's the Association of Pedestrian and Bicycle Professionals), there's an email listserve where folks share and discuss current best (and worst) practices in design and development from across the country and in the world. Thanks to being a part of this great group, I'm able to stay tuned to discussions on best practices, and try to bring the best to South Carolina's Upstate.
If you've ridden around any roundabouts, I'd love to hear your thoughts on what worked well and what fell short.