what program, or how do you keep track/list of clients/potential clients?

On the Mac platform, I was using Freelance. It has some really quirky things so now I just rely on Calendar and Address Book. Calendar has places for notes and reminders and you can set alarms for tasks which is nice. Address book does what the name says. Since they sync with my iPhone, it makes meetings really easy too.
Since I don't have a ton of clients (20-30 depending on the time of year), it seems to work really well.

Pretty basic for me.

I set up a database with about 3000 people:

name, title, company, address, city phone, and so on. I also have a column that is my DNE (do not email) if I get a request to unsubscribe. A column for keeping track of when I called/left message for a person, and if they are an a**h*le or seem like someone I'd like to work with. I also make a note as to the kind of work they look for, if they use stock, craigslist, or some other half backed supply chain.

A calender comes in handy to, so you remember to call someone back when they say call me in 6 months, a year, or decade.

Jonathan

I use Quickbooks to keep track of clients I did projects for or who I've submitted bids to.