We have a client that has big growth plans and they want to be able to have some of our annual fees, with them, billed out on a monthly basis. This is not SAAS fees, but you can call it that if it helps give me a recommendation. I need an easy way to put in what they owe each month and it e-mails them or is a system they can login to pay, or something else that will automate the administrative task of doing monthly billing.

As I mentioned to our new friend that wants to create an accounting system, QuickBooks doesn't do this well, but we do use QuickBooks as our accounting software, so integration with that would be a nice plus. I know I'm asking for a lot.

Any ideas?

Lisa