The spaghetti will land in a sunflower formation divided equally around the pot. This will help the pasta keep from sticking and start cooking each stand of spaghetti evenly. After a minute or so, give it a stir and all the stands will be submerged in the water separately. This is especially helpful if you have a pot that is wide, but not quite as tall as you might like.
No oil will be necessary. Boiling pasta with oil makes the finished pasta slippery, more difficult for the sauce to adhere. More pasta tips to share?