Setting up referral programs for your clients

Hello all,
This is more a question for those who do consulting and set up systems for their clients.

I'm wanting to set up a referral program for my business. I own a dog training business where we sell DVDs to a nationwide audience and one-on-one dog training services to people in the Utah area (sometimes beyond).

I know there are various WP plugins for the DVD sales where someone becomes an instant affiliate when they sign up.

I'm more interested in our brick and mortar business. I'm trying to figure out how to set up a referral program so that people refer their friends and family to come to our company to get their dog trained. I'm looking for something that makes it incredibly easy for someone to not only refer us but to also track back the results to them so they can get rewards, cash prizes, etc.

All of our clients have access to a membership part of our website so I was wondering if there was a simple way that someone could click on certain pieces of content and that it would give them the option to share that content (the content would be some sort of invitation) through email, facebook, twitter, etc. Ideally those that have been referred would come to the website where they'd opt in and then we'd somehow be able to manually look back at the end of every month and see which new clients came in through the referral system and by whose part they were referred.

So my questions are:
1- Do you know of any way to make that type of referral process happen with a plugin, script, other, etc.

2- Do you have any other ways that you find are very effective for encouraging, tracking, and rewarding referrals from customers?

Thanks.