We recently had a client using Rajesh's civicrm_offline_recurring_payment module, but they were wanting to also upgrade their CMS to Drupal 7, so we've put together an extension version which should now support any of the CMSes supported by Civi. You can install it via the Manage Extensions page, and it supports versions 4.1, 4.2 and 4.3 at the current time of writing.
The extension basically allows a Civi admin to set up recurring payments for contacts via the admin interface. When installed, the extension places a 'Setup Recurring Payment' button at the bottom of the Contributions tab for each contact record:
.. which, when clicked on, takes you through to the following form for setting up a recurring payment:
Once created, recurring payments will appear in a list on the previous page where you can go in later and edit them. To stop a recurring contribution, edit it and select the current date under 'End Date'.
Automatic creation of contributions is done via Civi's 'Scheduled Jobs'.
Firstly, consult the documentation here for setting up a crontab to run jobs automatically at the specified times.
Secondly, from the Civi menu, go to Administer -> System Settings -> Scheduled Jobs.
Locate the following job below:
.. and select Enable, under 'more', to enable the job.
That should be all really - it's a fairly simple bit of functionality, allowing admins to setup recurring contributions on behalf of the contact, whereas without the extension, you need to rely on the contact to set these up themselves (and have pages setup to allow them to do this). So obviously, it goes without saying that you should make sure your contacts are expecting you to do this, and have agreed to it.
We hope the extension is of some use - any problems, or anything I've forgotten to cover here, then don't hesitate to contact me on the forums here and I will attempt to help.
And many thanks should also go to Rajesh on the forums, for providing the original code.