Today after school my Pontiac didn't start as smoothly as it normally does, and while i was idling at the traffic light it was vibrating, quite noticably. I figure it is the spark plugs, what do you all think?

Anyways i bought the spark plugs but am having a very hard time taking the plug out, i read the how-to, i tried twisting and pulling but they won't budge.

How long do i twist for, i felt as if i "unlocked" the wire when i turned them, but they still didn't come out. Btw this is a Pontiac Bonneville 2001 (not supercharged)

The boot is more then likely just stuck to the porcelain. You will need to twist. Change the plugs and inspect them as you remove them. Also check the wires to make sure they are not grounding out. One thing you will want to check is the back plugs, #4 and #6, sometimes these wires get to close to the O2 sensor wire and can cause problems. Check that.