Strategypage says Iran is years away. The mullahs want to test to protect themselves from external and internal threats:
But such a test may be years away, because of the apparently slow progress in developing some key technologies needed for the weapons.
The post also says that the Sunni Arabs are worried about Iran getting nukes.
This leads to my next point: I've noted before that I don't know why we assume that Iranians will rally to the regime they hate if we strike the nuke facilities that the mullahs have (This article is interesting in this light). But on top of that, why do we assume that the Moslem world will object if we strike Iran?
Just because Shia and Persian Iran is hit, will Moslems in Indonesia care let alone Sunni Arab Moslems who fear Shia Persians? Will Pakistanis or Indian Moslems be upset?
Really, the Moslem world did not rage against the 1998 strikes against a Sunni-run Arab Iraq's WMD facilities, so why would the world's Moslems get upset on Iran's behalf?
Back to the timing issue, the timing issue of when Iran goes nuclear is perhaps unknowable. It may also depend on whether you are talking about the time to blow one and the time to weaponize one. Iran can surely blow a nuke built in place long before it can build one that fits in a bomb or missile warhead.
But we've missed so many nuclear events since we went nuclear that I have little confidence we can time action very precisely.
Action seems like it is coming as we declare we will not let Iran go nuclear and the Iranians tell everyone to just bugger off and mind our own business.