He leaves the League One side Huddersfield Town to join Sven-Goran Eriksson, for whom he worked as a coach at Manchester City.
Leeds United have extended the loans of George McCartney and Jason Brown.
Brown, on loan from Blackburn, came off the bench for Leeds against Ipswich on Saturday when Shaun Higgs was injured.
With Kasper Schmeichel also out of action, Brown is the only fit senior keeper at the club. He will stay fort a further month.
McCartney's loan from Sunderland has been extended by just two days, making him available to face Cardiff City on Monday October 25. The match was moved for TV coverage, prompting the small extension.
Millwall have announced a share issue worth £11million to secure investment in the club.
John Berylson, the club's American chairman who made his money in banking, is expected to increase his holding.