Whether or not these rumors have any substance, I'd like to examine the geopolitcal importance of Iran in the region, and why so much attention is focused on that country.
First of all, Iran is one of the few countries in the region that forms a crucial pivot between the Russia and its allies, on the one hand, and China and North Korea, on the other. There have been reports that these countries have all consulted with each other over stemming U.S. and Western European influence in the region, and particularly in countering any threats to Iran.
Iran is probably the most important country to both China and Russia in the region. It produces the most oil of any country not aligned to some extent with the "West." Together with the oil-producing countries of Central Asia it provides a counterbalance to the Gulf nations that avoid close relations with the communist powerhouses.
Regionally, Iran has emerged recently as a big player with major influence beyond it borders. With the performance of Iranian-sponsored Hezbollah in the recent war with Israel, the nation has never looked so powerful. It is also known that Tehran now has warm relations with Syria and Hamas, and that all sides have looked to Iran for leadership in handling the conflict with Israel and the U.S.
Indigenous arms industry
The country now stands as the only regional nation capable of producing rather advanced arnaments, some of which are already competing in the international arms market.
During the war with Iraq, the Iranian military nearly collapsed in the beginning due to the large numbers of military officers, pilots and techicians who deserted, some fleeing the country, after the fall of the Shah.
Slowly, Iran rebuilt its armed forces recruiting assistance from abroad, from China, North Korea and Russia.
Together with North Korea, it has worked impressively over the last 18 years to develop a budding arms-producing capability.
Iran can manufacture its own ballistic missiles, anti-ship missiles, air defense systems, drones, tanks and other military equipment. It also purchases advanced weapons systems from Russia and China.
There is disagreement among experts over Iran's ability to fight in case it is attacked by the U.S. and/or Israel.
Taking a cue from North Korea, Iran has constructed many of its nuclear labs and facilities underground in fortified structures. North Korea is the most fortified country in the world with about twice the amount of tunnels used by North Vietnam to defend roughly the same amount of land during the Vietnam War. And the largest North Korean tunnels are burrowed through solid granite usually in rugged mountainous country.
Although not as well-entrenched as North Korea, Iran has nevertheless made substantial efforts to protect its facilities from attacks like the Israeli strike that took down Iraq's nuclear plant project.
Counterattack as deterrent
It is also widely-believed that Iran hopes to deter an attack with the threat of a devastating counterattack using primarily its missile and heavy artillery units.
The Iranians are reported to have obtained advanced Sunburn and Yakhonts anti-ship missiles from Ukraine. These supersonic missiles are thought to be capable of defeating any known ship defense system. They can use these along with Chinese Silkworm and their own indigenous Kosar missile to cutoff shipping lanes into the Persian Gulf.
Presumbably they could inflict serious damage on any naval ships stationed in the Persian Gulf. The Iranians are known to have developed three types of unmanned aerial vehicles (UAV) which could be used for long-range targeting. Israel has claimed that one of these UAVs flew a reconnaisance mission over Israel, and Iran has claimed that it once shadowed the USS Ronald Reagan for 25 minutes without detection.
Iran may also have two Russian-made Mainstay AWACS aircraft, which could provide additional targeting ability, if protected by a force of modern aircraft consisting according to some reports of 40 Mig-29 Fulcrums, 26 Su-27 Flankers and 24 Mig-31 Foxhounds.
The Iranians are also known to station mobile or "pop-out" cave-based radars and other targeting equipment on some of their high mountains near the coast and in the islands off their coast.
In addition to attacking naval and commercial shipping, Iran has invested heavily in other missile strike capability. There are some substantial reports, for example, that Tehran was able to smuggle Kh-55 long-range cruise missiles out of Ukraine. These missiles are the equivalent of the U.S. Tomahawk.
Several advanced intermediate-range missiles including one with multiple independently-targeted warheads exist in the Iranian arsenal. They have also recently imported land-mobile missiles from North Korea that can strike targets in Europe.
As with Hezbollah rocket reserves, there are many analysts who think the Iranian missile stockpiles may be greatly underestimated. For example, some think Tehran may have from a few thousand to several thousand anti-ship missiles of all kinds from Silkworms to Exocets.
The estimated number of ballistic missiles of Scud-type and higher ranges from a few hundred to thousands.
Iran is also known to have invested money in massive tube artillery from 240mm to 355mm in diameter, which could be used to counterstrike against Western forces in Iraq should Iran be attacked.
According to some reports, the Iranian defense industry, probably with some foreign help, has conducted upgrades on older U.S. aircraft systems like the F-4, F-5 and F-14. The country also produces its own fighter aircraft, air defense missiles and guns. It is believed that Iran will practice point defense to both protect high-value sites and to guard its offensive missile and artillery units.
In comparison to North Korea, Iran has invested surprisingly little in upgrading its land army. It's mobile forces and overall strength are just a fraction of that of the North Koreans despite having much more territory to defend. This indicates Iran is not particularly worried about a massive ground invasion.
Their strategy in case of attack is to draw China, Russia and North Korea into the conflict as much as possible, to defend strategic sites, and to counterattack vigorously with its missile and artillery force in hopes of attaining a quick cessation of hostilities. It's main targets would be U.S. forces in the Persian Gulf and Iraq, and together with Hezbollah it would likely strike at targets in Israel. Attacks could also be expected against oil tankers and possibly oil facilities in the Gulf Arab states.