Jonathan, just to clarify, I think that the Kurdish group you are refering to that conducts operations in Iran is PJAK, which is an ally but not the same group as the PKK. I believe they both belong to a larger umbrella group but am not sure about the details.

Here's what the New York Times says about PKK vs. PJAK:

"The guerrillas from the Party for Free Life in Kurdistan, or P.J.A.K., have been waging a "deadly insurgency in Iran and they are an offshoot of the Kurdistan Workers’ Party, known as the P.K.K., the Kurdish guerrillas who fight Turkey.

"Like the P.K.K., the Iranian Kurds control much of the craggy, boulder-strewn frontier and routinely ambush patrols on the other side. But while the Americans call the P.K.K. terrorists, guerrilla commanders say P.J.A.K. has had “direct or indirect discussions” with American officials. They would not divulge any details of the discussions or the level of the officials involved, but they noted that the group’s leader, Rahman Haj-Ahmadi, visited Washington last summer.

"Biryar Gabar, one of 11 members of the group’s leadership, said there had been “normal dialogue” with American officials, declining specifics. One of his bodyguards said officials of the group met with Americans in Kirkuk last year.

"Iranian officials have accused the United States of supplying the fighters and using them in a proxy war, though those assertions were denied by the American military. “The consensus is that U.S. forces are not working with or advising the P.J.A.K.,” said an American military spokesman in Baghdad, Cmdr. Scott Rye of the Navy.

"A senior American diplomat said that there had not been any official contacts with the group and that he was unaware of its having received any support from the United States. He also said that Mr. Haj-Ahmadi, while in Washington, did not meet with administration officials.

"Because the P.K.K. is on the State Department’s list of terrorist organizations and aiding such groups is illegal, the United States is eager to avoid any hint of cooperation with the P.J.A.K.

"Guerrilla leaders said the Americans classify the P.K.K. as a terrorist group because it is fighting Turkey, an important American ally, while the P.J.A.K. is not labeled as such because it is fighting Iran.

"In fact, the two groups appear to a large extent to be one and the same, and share the same goal: fighting campaigns to win new autonomy and rights for Kurds in Iran and Turkey. They share leadership, logistics and allegiance to Abdullah Ocalan, the P.K.K. leader imprisoned in Turkey."

On the 10/18/07 James Zogby there was an American ambassador taking question and I was able to ask him why was the USA arming the PKK and those weapons were being used against Turkey our NATO ally. He did not deny this obvious conclusion saying the now famous Republican chorus "I don't know who's arming the PKK" not a denial. Just how insane is it to give weapons, aide, to the PKK to use against Iran and either asking or assuming they won't use these weapons against Turkey. The PKK has no loyalty to the USA. If anything they would harbor resentments because of the betrayal by Bush 1 when he encouraged the Kurds to revolt against Sadaam, they did so, and were left out in the cold to hang and were slaughtered, gassed, bombed, shot and otherwise by Sadaam to put down the Bush inspired revolt with the implication of aide to the Kurds for doing so.This scenario of Turkey and the Kurds was predicted before the 2003 invasion.