How to accept recurring payments in a subscription site?

[eluser]Kevin Smith[/eluser]
So what we're doing here in a software-as-a-service kind of thing. And I know it's typically bad practice to store the user's credit card numbers on our server, so I was thinking I'd have to use something like Authorize.Net's CIM, which stores the user's CC numbers on their end and handles the recurring billing.

I suppose I was really wondering if anyone had experience with this sort of thing and if they could give me some places to start in my development. Has anyone used Authorize.Net's CIM to do recurring billing before?

(I don't need an entire web store, so I think OSCommerce and Zencart would be overkill.)