Barry moves from Mark Cavendish's Team Columbia-HTC
British squad Team Sky have boosted their 2010 squad by recruiting three more riders, taking the total to 19.
The new team have signed up Canadian Michael Barry, Chris Sutton from Australia and Belgian Serge Pauwels.
GB star Bradley Wiggins has been linked with a move to Sky but is contracted to Garmin-Slipstream until 2010.
Team Sky boss Dave Brailsford said: "These new signings will strengthen our profile even further, with regards to the classics and big-stage races."
Barry, 33, rode for the US Postal Service alongside Lance Armstrong from 2002 and joins Sky from Mark Cavendish's Team Columbia-HTC.
Sutton, 25, who is the nephew of British Cycling head coach Shane Sutton, was second in the 2009 Tour of Britain, riding for Garmin-Slipstream.
Pauwels, 25, joins Sky from Cervelo Test Team and was second on stage 15 of the Giro d'Italia in May.
Brailsford added: "In Michael we have a real ambassador of the sport and the kind of rider that will make a superb captain on the road.
"Chris and Serge are two really exciting talents who have already achieved success with strong results over the last couple of seasons."
Sky, funded by broadcaster BSkyB, were set up in 2009 and have already signed up Norwegian star Edvald Boasson Hagen, 22, and six Britons.
The team expect to take part in the Tour de France in 2010, with the aim of winning the tournament four years later.
Team Sky squad so far:
Kurt Arvesen - 34, from Norway; has won stages of the Tour de France and Giro d'Italia and will be a mentor for young riders; part of Saxo Bank squad that included 2008 Tour de France winner Carlos Sastre and Frank and Andy Schleck.
John Lee Augustyn - 23, from South Africa; Barloworld team-mate of Thomas and Froome during 2008 Tour de France; has potential to be a great climber.
Michael Barry - 33, from Canada; Team Columbia-HTC team-mate of Mark Cavendish; rode with Lance Armstrong for US Postal Service.
Edvald Boasson Hagen - 22, from Norway; currently sits third in the UCI rankings, having won a stage in this year's Giro d'Italia.
Kjell Carlstrom - 32, from Finland; a specialist climber, he has ridden all three Grand Tours and is a stage winner in Paris-Nice.
Steve Cummings - 28, from Birkenhead; part of pursuit teams that won gold at 2005 World Championships and 2006 Commonwealth Games and silver at the 2004 Olympics.
Russell Downing - 31, from Rotherham; winner of 2009 Tour of Ireland; one of the most successful ever GB-based professionals.
Juan Antonio Flecha - 31, from Spain; has 10 years' professional experience, including a Tour de France stage win in 2003; known as a Classics specialist.
Chris Froome - 24, born in Nairobi, Kenya; became British-registered in 2008; has completed two Tours de France.
Simon Gerrans - 29, from Australia; has won stages of all three Grand Tours this year and the 2008 Tour Down Under.
Greg Henderson - 31, from New Zealand; world scratch race champion on the track in 2004; has recorded nine victories with Columbia in 2009, including the Tour of Spain.
Peter Kennaugh - 20, from Isle of Man; British Under-23 Champion who is dominating the Under-23 calendar in Italy; partnered fellow Manxman Mark Cavendish in madison at 2009 world track championships.
Thomas Lovkvist - 25, from Sweden; a five-year pro who wore the leader's jersey during this year's Giro d'Italia as part of Columbia HTC squad and could contend for overall tour wins.
Lars Petter Nordhaug - 25, from Norway; former mountain-biker who switched to the road and became Norwegian national champion; runner-up to Russell Downing in the 2009 Tour of Ireland.
Serge Pauwels - 25, from Belgium; second in stage 15 of Giro d'Italia in 2009.
Morris Possoni - 25, from Italy; wore the best young rider jersey during the 2008 Giro d'Italia as part of the Columbia squad.
Ian Stannard - 22, from Chelmsford; came third in 2008 Tour of Britain and rode 2009 Giro d'Italia.
Chris Sutton - 25, from Australia; won opening stage of 2009 Tour of Britain and finished second overall. Nephew of British Cycling boss Shane Sutton.
Geraint Thomas - 23, from Cardiff; youngest rider in 2007 Tour de France; won gold in team pursuit at Beijing Olympics.