I want to install a ceiling fan in a room where there's no fan?

Is there an existing light fixture that you would remove for the fan? How about any wall switches, got any?

Once again I second Ballenger's answer.

Ceiling, now that you are here, I am going back to plumbing for the night.

Maria, that's no problem. Just make sure you brace the electrical box to support the fan. Lowe's and Home Depot sell a metal box with a sliding bar that you stick up inside the hole where your existing light box was (You will have to remove it unless it was planned to have a heavy fixture hanging from it) and adjust it out tight against the ceiling joists/trusses. You'll have to pull the cord to turn the fan on and off unless you want to just have the fan come on every time you turn the light switch on. Hope it goes well.

I'll be gone again starting Sunday :)