@hackage network-bitcoin1.1.0

This can be used to send Bitcoins, query balances, etc. It requires the Bitcoin daemon to be running and accessible via HTTP.

import Network.Bitcoin

main = do
   balance <- getBalance auth
   putStrLn $ show balance ++ " BTC"
 where
   auth = Auth "http://127.0.0.1:8332" "user" "password"

To learn more about Bitcoin, see http://www.bitcoin.org.