I've been using BI to render objects as meshes using freestyle edges. I'm now trying to learn to use Cycles. Is it possible to render freestyle edges in Cycles? If so, how?
No, freestyle is not yet supported in Cycles (and I'm not sure it ever will be directly supported). You could work around the issue by using render layers and grabbing only the freestyle pass from BI:
Then mixing it with the Cycles pass in the compositor.
This is now in master, and will be in 2.72.
This is possible using this experimental patch, which may be included in master eventually.