Iran has a vested interest in the outcome of January's elections. Perhaps I should say "elections", but that is yet to be decided. Anyway, they will most likely hold off any overtly provocative actions until then. It is nearly inconceivable (nearly) that in a free and fair Iraqi election, a pro-shiite, pro-Iran party doesn't come to power. Iran is working hard under the table, via their military (BADR) and political (SCIRI) arms in Iraq to ensure that this does happen. If a pro-Iran, shiite party comes to power, then they have shored up their flank and take a step towards becoming the regional hegemon that they aspire to be. However, in the event that a pro-Iran Shiite party doesn't come to power, the assumption will be that the election was unfair (both in Iran and among the Shiite majority in Iraq), and then I would expect Iran to begin more overt actions to 1) arm and instigate Shiite resistance, which will flare up after an election loss, 2) proceed with their nuclear program, and 3) possibly make some overtures towards al-Qai'da to exact a reaction from the US. It's unrealistic (in my opinion) for Iran to expect the US to "change" the results of the election in order to get concessions from Iran. It's equally unrealistic for the US to invade Iran while still bogged down in Iraq (though I wouldn't be surprised by airstrikes). Ultimately, US failure in Iraq benefits Iran only if the Shiites lose the election, so I would expect Iran to be very quiet, even make some concessions on reprocessing to the Europeans until the elections have passed. If the Shiites win, and do so convincingly (i.e. they actually get 60% of the power commensurate with their population, something that the US is working hard to prevent), then Iran will congratulate them and attempt to "rejoin the world community" and drop their a-bomb program in exchange for lifted sanctions. The Bush administration will have a difficult time declining this offer (peace dividend?...), but this election result will ultimately end with the fall of the House of Saud as Saudi and Iraqi sunnis become even more polarized against secular authorities. If the Shiites don't win, then Iran will incite a renewed insurgency in the South, Iraq will fall into chaos, the US will be overwhelmed (because the Sunni regions will likely reject the outcome as well), and when the US withdraws and Iraq falls into chaos, the House of Saud will follow shortly there after. Which, of course, has been bin Laden's goal all along. That, in turn, is why there won't be any major terrorist attacks in the US for the next few years, because bin Laden's effort is better spent manipulating the efforts in Iraq and Saudi Arabia, and the US public won't support prolongued casulaties in Iraq if there is no longer a perceived threat in the "homeland".
Any theory that bin Laden/al-Qai'da will conduct another attack on America must explain how that action will bring about the fall of the House of Saud, as that is their ultimate goal. Everything else (9/11 included) is intended to realize that.
I give King Fahd & Co. 3 years.
Who knows, could happen...