It's not necessarily a big deal. There's a good chance you can use the existing wiring, but probably not the existing box in the ceiling. Go to your local big-box store and ask about ceiling fan-rated electrical boxes. There are several styles available, depending on whether you need to mount the fan in open space between two joists, or up against the side of a joist, or directly under a joist. After disconnecting the wiring from the old fixture, you'll have to disentangle it from the old box and pull it into the new box as you install it. Hopefully the house is new enough that the wiring is romex; if it's full of original 1950's wiring with insulation that has become brittle, it could become a bigger project.

BTW, I'm very happy with the Minka Aire fan I just installed over my dining table. It has no switch chains at all. Instead, it has a remote control that controls the light levels and fan speeds, and a wall switch that uses the same radio receiver to control the same functions, with no fancy wiring required.

Just did this. Took less than an hour. You'll need to check to see whether the light fixture box was braced into the ceiling otherwise you'll need to install a brace which'll add some minutes to the install time.