I haven't seen evidence that Wilson said that Cheney sent him on the trip to Niger either. I can understand why people think that Wilson said that, but thus far, no evidence has been presented to support that supposition.
As to the classified nature of Plame's involvement in getting her husband the gig to Niger, it was discuss, I think, in the Senate hearings which were televised. And I don't think the memo which was found, where Plame recommended her husband for the job, is classified.
But you've been able to delve into this more carefully than I have been able to, due to time constraints this week on my part.
According to the orginal op-ed piece he did .. Wilson said he was told by the CIA ... aka his wife
http://foi.missouri.edu/terrorintelligence/whatididnt.html
In February 2002, I was informed by officials at the Central Intelligence Agency that Vice President Dick Cheney's office had questions about a particular intelligence report. While I never saw the report, I was told that it referred to a memorandum of agreement that documented the sale of uranium yellowcake — a form of lightly processed ore — by Niger to Iraq in the late 1990's. The agency officials asked if I would travel to Niger to check out the story so they could provide a response to the vice president's office.
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BTW ... Wilson apparently also said this
http://www.freerepublic.com/focus/f-news/993121/posts
"Neo-conservatives and religious conservatives have hijacked this administration, and I consider myself on a personal mission to destroy both." Those are the words of Ambassador Joseph Wilson, who will certainly be a household name for weeks to come
A Letter from Ambassador Joe Wilson (Barf Warning)
Email (John Kerry) | Joe Wilson
http://www.freerepublic.com/focus/f-news/1014065/posts
(snip)
Dear Friend,
In February 2002, George W. Bush's Administration sent me to Africa to investigate claims that Saddam Hussein was seeking to buy materials for weapons of mass destruction. In early March, I provided a detailed briefing to the C.I.A; I concluded that Iraq had most likely not tried to buy uranium in Niger. We know the rest of the story