What sound card do you have? Assuming that its just the built in one, you would need to get some sort of preamp. This will provide phantom power as well as bring the signal level up from mic level to line level. You cannot just go straight into the sound card without preamping in some manner. You can either buy a dedicated preamp unit, or buy a small mixer.
Preamp-wise, the M-Audio DMP3 is recommended quite often on this board. It is a 2 channel preamp, so you would be able to use another mic with it when you get one. It costs about $160, i believe? Not sure, but somewhere around there.
If you want to go the small mixer route, I have heard people say that the Yamaha MG series of mixers do fairly well for the price. These are a bit cheaper, depending on the model, but I think you could get one for around $100 or so.
Let us know more about your budget and the rest of your setup (unless you're just starting and the mic and computer is your setup!)
Anyone else, feel free to correct anything I may have screwed up or offer their own suggestions.
Adios.
P.S. Make sure, if you are going to use the built-in soundcard, use the LINE input NOT the mic input. Trust me, it makes a huge difference, although it would be better to upgrade your sound card.
