I'm new to Blender and am going through the Noob to Pro tutorial. I've made it up to creating the wheel for the jeep and I can't figure out how to select the tire without selecting the hub cap, while in Object mode. Selecting one with the RMB selects the other. Selecting 'A' repeatedly toggles both on and off. Is there a way to make these two separate objects so that I can select them independently?

I'm using 2.43.

Thanks,
6DOF

It turns out all I needed to do was go in to Edit Mode, select the vertices of one object and press P.

I tried this in Object Mode and it didn't work.