Why is my Alero jerking to the right when I hit about 70?
Probably because the Grim Reaper is following you around. Have you happened to also notice an unusually large number of safes and pianos hanging over your head as you walk down the street?
Your description of the problem is pretty vague so I could ask some questions for clarity, but no matter. You need to take it to a good local front end/alignment shop and have the tires and front end inspected.