The light currently just has a pull cord and I want a simple wall switch instead. The power runs to the light from the other side of the room. Do I just need to run a wire from the switch to the light and tie it in or have the power come to the switch first and then to the light? How does it tie into the light and current power. I've tried to find a simple diagram of how the wiring works but can't find anything.

For a retro fit, the easiest thing might be run a new cable from the light to where you want the switch. You can use surface mount boxes and conduit that don't look too bad. Remove the black wire from the light, and connect it to the black wire of the new cable. Connect the white wire of the new cable to where the black wire was connected. Then at the switch, connect the black and white wires to the brass screws of the switch. Connect the bare wires at the light, and also to the housing of the light and the green screw on the switch. The bare wires make sure if anything ever goes wrong, the breaker trips and shut the power of before killing somebody or setting the house on fire.

You other alternative would be to cut into the wire that feeds the light, cut the black wire, and connect the 2 ends to the switch. However, the switch and any connections must be in a box that is assessable. The cut wire will be so short it will be hard to work with unless you can pull a little more cable out of the wall. Modern cables are stapled to the stud and difficult to move much. If you house is old enough that it used metal boxes with clamps in the box for the cables, it may be a little easier.

One thing... common practice says not to switch the black. In the light where you are running your switchloop (the wire that runs between the switch and the fixture) you would tie the black from the house side to the white going down to the switch. And the black coming back from the switch to the black on your fixture.

Here is what I am talking about

Also the surfaced mounted methid of wireing that labman was talking about is here WIREMOLD