Iran needs to be dealt with no doubt, but this is not the time. If they provoke a war - and it looks like they might try - then I would fully support action. But in terms of attacking them over British sailors, no. A similar thing happened a few years ago with China, and Colin Powell was able to diplomatically smooth out the issue.
Iran is nearly everything the administration claimed Iraq was. They have weapons of mass destruction, they support "terrorists", they are a world destabalizer. The world would indeed be a better place without Iran having access to nuclear weapons. In fact during the buildup to war many Democrats and leftists used talking points along the line of "Iraq is not the dangerous threat, NK and Iran are. But it seems like if you have weapons you don't get attacked". Well now they've changed their minds.
We are too stretched out in Iraq to possibly wage a ground war with Iran. While we could easily destroy all of Iran's nuclear capibilities with an air attack, the consequences would be huge. As a couple people have said on GAF, Iran is already in control of various proxy groups, and could easily attack the US from the inside. To make matters worse, they could totally ruin the Iraq situation. They are already an influence, but attacking them would give an excuse to really fuck things up.
So no, I do not support any unprovoked attack on Iran, nor do I believe there will be one anytime soon unless Iran begs for it. Many on the left have been predicting and almost wishing for an attack for a long time now. Scott Ritter definitively said that his sources confirmed there would be an attack on Iran in July...2005. So I'm not interested in all by this parade of fearmongering, for once coming from the left. Bush has severed many ties in the Republican party due to the mess he has created, but there is no way in hell the Republicans would sit back and let him ruin their chances in not only the presidentual race, but the house and senate races as well. Another unprovoked war would destroy the party for another decade perhaps