This is a huge step you are contemplating. Be sure you are ready for it and ready to spend some dollars.
There are several satellite tracking software packages available. Some of them work better than others. While they all track satellites OK, the interface to a rotator varies in ease and functionality. If you go to www.amsat.org
and go to the store, you can download a trial version of SatPC32. The download is a full blown version, but unless you pay your money and get your key, you will need to enter your QTH information each time you start it up. The trial version will give you the opportunity to play with it and see if it will meet your needs. Another program is called NOVA. It can be had at http://www.nlsa.com/
I like the looks of NOVA better, but SatPC32 is easy to get loaded and working. Some others programs to play with are Orbitron and Ham Radio Deluxe. I have not tried to interface these, but from what I am told, each has its challenges.
OK so now you have some software loaded. You are going to need an ALT/AZ rotator to point your antenna(s). The Yaesu G5500 is one good choice if you have about $700. Then you need an interface to go between the rotator controller and your PC. The LVB tracker is a nice one and it can be had at www.amsat.org
also - $220.
You will probably want a couple of new antennas as well. The M2 circular polarized yagis will fit the bill. You will need one for 2 meter and 1 for 70 cm - $600. You can get by with an arrow antenna but if you buy all of the above, you will probably want to upgrade your antennas also.
A preamp would be good also, but not absolutely necessary.
You will also need a good solid mast or a tower to mount all of this onto. Lots of bucks involved there. And it is not going to much of a portable system. It will take up a good piece of real estate and is quite heavy, so don't plan on dragging it to the park on weekends.
There you go. I am not trying to discourage you. If you want to do it - go for it. Just be prepared to spend some $. You don't need all of this stuff to make casual satellite contacts, and frankly, the number of viable satellites is dwindling.
Why not just get an arrow antenna and use a handheld for a while until you can figure out you just can't live without a full blown satellite station? You will learn a great deal and have a good time doing it. If you decide it isn't what you thought it would be, you won't be out a great deal of money.
I am in the process of putting together two systems for an ARISS contact. The second system use a static eggbeater type antenna system so it isn't nearly as sophisticated as the primary system. Never the less, I have about $3,000 into the two systems, not including the radios, so it is not a cheap endeavor. If you don't have a source of free stuff, you are looking at about $2,000 to put together a reasonable system not counting the radio(s).
Good luck to you. I hope this is the type of information you wanted.