There are a couple ways to center your steering wheel.

The way I've done it is to undo the rag joint on the steering shaft. Have 1 person hold the wheel where it needs to be & then bolt the rag joint back up.

Also, you can use a steering wheel puller ($9 at Kragen).  You just pull the wheel off of the splines, then reinstall it where it should be.  It's a piece of cake w/the puller, just make sure you torque to specs because if you overtorque the nut, your retainer clip will pop out and not ride on the bearings anymore. You will know if it has popped loose if your steering wheel pulls in and out and feels tight when turning.  Be aware however that some steering columns/wheels have keyed splines so there is only one way they go together.