April 26, 2008, Edinburgh, venue to be determined.

Promoted by Warren, Guzman's promoters have announced he's signed the contract.

its on boxingscene

I think Guzman handles him, saying that as a huge fan but still I'm not that worried.

Edit- the articles titled Guzman-Warren set but now that I look at it a second time it only says that Guzman's signed, there's nothing really from Warren. He did win the purse bid and the fight is his promotion in Edinburgh though.