The records of 12,000 servicemen and women decorated for their courage during World War II are to be made available in an online database.
The National Archives has put new eye-witness material online
The files, collected by the National Archives in Kew, will cover all those given awards for bravery in north west Europe between D-Day and the war's end.
Thousands of wartime eyewitness memories of civilians and soldiers can also be searched on a web catalogue set up by the Second World War Experience Centre, in Leeds.
Extracts from letters, diaries, audio clips and photographs will all be made available online.
The National Archives hopes it will mean people across the UK can access more information about World War II online before visiting the archives.
A spokesman said they hoped to complete the database of bravery awards by May 2005, to mark 60 years since the conflict ended.
People can already search the names of 600 soldiers and officers to find descriptions of their valiant acts.
Among them is Private Thompson, 19, who on his first duty repeatedly fired at a sniper to allow his comrades to make their way through a gap.
He managed to guide another soldier to safety after staying behind the rest of his group.
His superior officer, in a recommendation for an award, said: "The courage, resource and initiative shown by this young soldier was a remarkable example."
Bruno Derrick, historian at the National Archives, said: "The files are also rich in stories of human endurance such as an officer who, after being wounded in three places, carried on with his men and managed to take a village and approximately 50 prisoners.
"It will be a huge boost for veterans, their families and military historians."
Among more than 5,000 first-hand accounts of wartime life on the Access to Archives catalogue are the memoirs of Keith Nurse, from Kent, who recounts his experience as a seven-year-old in north Wales in 1944.
He describes how US troops billeted with them left one day for the Normandy beaches.
"Then, when the time came, our four Yanks suddenly disappeared, almost without trace or warning, in the middle of the night - bunks and all... Deep down we feared the worst."
Thousands of first-hand accounts of wartime Britain are available
A 12-year-old boy describes the Home Front preparations for D-Day, saying: "By the spring of 1944, in Britain, one had to be an idiot not to know something 'big' was going to happen - soon."
The computer catalogue is the result of collaboration between the Second World War Experience Centre, in Leeds, and Access to Archives, co-ordinated by the National Archives and British Library.
More than 1,000 photographs showing the secret pipelines laid under the English Channel to keep the D-Day Allied invasion fuelled have also gone on display at Kew.
The National Archives pictures show how the pumping stations for the operation - named Pluto (Pipeline Under The Ocean) - were disguised as harmless ice cream shops and bungalows.
Without this fuel supply, the break-out from the Normandy beaches would have been impossible, a National Archives spokesman said.
The release of information comes in the run-up to the 60th anniversary of the Allied invasion, to be celebrated over the weekend of 5-6 June.