Thanks for posting this. At our local lefty message board, they were peddeling this just yesterday. Not anymore.
I'm struggling to understand which memo is forged. There was more than one 'leaked' memo in the election run-up. One was the original text of Goldsmith's advice to Blair, quibbling about the legality of the war. That was leaked and then officially released by Downing Street and hence presumably isn't fake. The other was a briefing from (purportedly) some Downing St official about Blair's meeting with Mr Bush and the war planning. At the time the second one came out, one of Blair's officals made a 'so what?' statement that didn't appear to dispute its authenticity, but only its relevance to anything important.
I believe the latter is the one that has your Democrats all stirred up, but the rebuttal article mentions something signed by Goldsmith rather than one of Blair's political advisers as in the other memo. Which sounds like a fake Goldsmith memo as opposed to the real Goldsmith memo or the briefing about planning on Iraq. It's all rather confusing.