How do I keep track of the private money I owe?

[Thomas B.]

I was just wondering if anyone knew of a good website or program to track private money lending?

My parents helped me finance a property and I am paying them back over 3 years. I'd like to have a program that will take into account every payment and overpayment and calculate it out amortized over 3 years with the interest rate that we've agreed upon.

Thanks,
Tom