The domain name JOHNPAULIII.COM is available for sale on AfterNic for $1950. It was registered in 1999.
POPEJOHNPAULIII.COM re-directs to catholichomeschooler.com. It was registered this past January.
Names such as Lando II, Formosus II and Agatho II, papal names not re-used, in one case, since 681, are still available. Hat tip Volokh.