I read somewhere, that payment-requests might be possible with bitcoin in a future.
Idea behind Bitcoin is that nobody else except you can take your BTC, so it should be obvious that you have to get active to send some BTC out
Perhaps an Onlinewallet supports recurring payments once it got credited with some Bitcoins!
In the meantime just use the API of bitcoin-qt with Autostart:
1.) Always start bitcoin-qt.exe with Parameter "-server -rpcuser=user -rpcpassword=password -rpcallowip=127.0.0.1 -rpcport=1234".
2.) Create timed schedule for execution (e.g. Schedule Planner in Windows every 1st of month):
bitcoin-qt.exe -rpcconnect=127.0.0.1 -rpcuser=user -rpcpassword=password -rpcport=1234 sendtoaddress 1dice6YgEVBf88erBFra9BHf6ZMoyvG88 1.0 monthly-satoshi-dice-payment
For more commands, see
https://en.bitcoin.it/wiki/Original_Bitcoin_client/API_calls_list And you have your standing order :-)
Attention: You open a door to viruses who already infected your computer to get easier to your BTC! It does not matter which username or password you choose. It will be always visible in process list. So be sure you do not use a wallet with many BTC, or you have a save (TM) computer