Prospect organization & maximizing leads

I'm looking for input on how everyone manages their prospects. What organizational method do you use to keep track of contact info. Not only how you manage the names and phone numbers, but after you've made initial contact and are given follow up instructions (ie: Decision maker only comes in on Wed mornings, follow up with new owner in 6 weeks, call back in 2 days, etc...). How do you maximize this information to make the most effective use of this contact information and follow through?