Account/Contract Management

Hi all. I've just come across this site today and I've already found some excellent information so thanks very much already!

Maybe someone can help me with a problem I'm having at the moment that I should have sorted before I went freelance over a year ago!

I'm looking for a script or program that can manage contracts/accounts. For example, for one client I may include a domain name and hosting for a set fee per year. For another I may simply hold a domain only for two years. I need a way to remind me to bill the client when the period ends for whatever the deal is.

I do invoicing separately so no payment or billing system is necessary. Similarly, I have just implemented a CRM that covers most of the client management but the 'contract management/tracking' is the only feature that is missing. I simply need a system to track the contracts and notify me when they expire. Ideally, I'd ideally like to find something open source as the required features are not that many.

Can anyone advise me on what may be suitable? Any help is appreciated!

Thanks!