Colin Powell's comments on Iran are not going to be as bad as some will have you believe.
At this point, we cannot attack Iran. This is because the anti-war movement and the mainstream media have made preemption a non-starter due to their lies (see the Jemil Hussein controversy for one such example).
We did discover WMD in Iraq (at least 500 shells for chemical weapons, including sarin and mustard gas). Iraq did have ties to al-Qaeda and other terrorist groups.
As such, we won't be dealing with Iran until Ahmadinejad does something stupid. Then we will be reacting. I only hope that we will not be forced into an over-reaction.