Sounds like the Guardian article got it right. From the Guardian article:

Scientists and economists have been offered $10,000 each by a lobby group funded by one of the world's largest oil companies to undermine a major climate change report due to be published today.

Travel expenses and additional payments were also offered.

From the AEI memos soliciting works:

If you .... are agreeable to being authors, AEI will offer an honoraria of $10,000. The essay should be in the range of $7,500 to 10,000 words.. We intend to hold a series of small conferences and seminars in Washington and elsewhere to coincide with the release of both the FAR... for which we can provide travel expenses and additional honoraria if you are able to participate.

AEI is willing to offer honoraria of up to $10,000 for participating authors, for essays... and we are keen to work with you to refine an appropriate topic.


>>http://www.crooksandliars.com/2007/02/04/scientists-offered-cash-to-dispute-climate-change/
>
>Looks like the original premise of this thread is bogus.
>
>http://online.wsj.com/article_email/SB117099332237703363-lMyQjAxMDE3NzAwOTkwOTkzWj.html
>
>Now that's funny!