Trial period

Is there a way to setup a trial period? I would like to offer the first 30 days or so for free. But they need to input their credit card. Althougth they woundn't be charge until after 30 days.

Hi Scott,
I am after this functionality too! Currently I have to to ths mannually by setting up a 'free $0 plan' and then manually edit the receipt to add the user to this free role (I wanted to take advantage of the subscription tool reminder job to automatically invite free subscribers to upgrade).
But I am sure a better way to achieve this automatically is for the Subscription Tool Module to have 'free option tick box' plan for Admin so if the subscriber choose this option then the module will bypass PayPal payment and Automatically added the user to the specified role for the 'free' plan ?

Please let me know if this can be done?