The Mets have apparently traded Ramon Castro to the White Sox in exchange for RHP Lance Broadway. So, that just happened.
Broadway has a career minor league ERA of 4.10 and a WHIP of 1.43. He was the Sox's first round pick -- 15th overall -- in the 2005 draft. Omar Minaya mentioned on SNY that the Mets will send some cash to the White Sox.
Broadway has a solid 1.70 career GB/FB rate as a minor leaguer.
UPDATE: Broadway was John Sickels's #4 White Sox prospect for 2006 and 2007, He was #6 for 2008. He fell out of the Top 20 for 2009.