Luton have signed former Peterborough and Brighton striker Craig Mackail-Smith on a two-year deal.
Norwich City have completed the signing of goalkeeper Jake Kean following his release from Blackburn Rovers.
Derby have signed Norwich striker Chris Martin on an initial one-month loan.
The 24-year-old forward, who recently returned from a loan spell with npower League One leaders Swindon, fills the void left by Theo Robinson's move to Huddersfield on Friday.
Martin, who has played just three times under Canaries boss Chris Hughton, is expected to go into the squad to face Watford at Vicarage Road on Saturday.
"We're pleased Chris has decided to join us and provide another option in attack," manager Nigel Clough told the club's official website.
"With Theo asking to go out on loan, there was obviously a need to bring in a replacement once a deal with Huddersfield was agreed. Initially, Chris is here for a month and we'll just take things from there."
Martin spent a spell last season on loan at fellow Championship side Crystal Palace, netting seven times including two against the Rams.