Well, just to keep everyone updated, I suddenly remembered that cabal-install now writes log information! =D  So I looked in the logs and found that I had indeed recently installed network-2.1.0.0 when trying to upgrade the urlcheck package.  So I upgraded to the latest version of network (2.2.0.0) and now everything is peachy again.  So, it seems that network-2.1.0.0 was the culprit...

-Brent