The Sun quoted the England stopper as saying: "Just before the shootout I was looking at an I-pod with goalkeeping coach Eric Steele. On it were images of Spurs taking penalties. I'd been told if O'Hara took a kick that he would probably go to my left. It was great that was exactly what happened and I managed to get a hand to it."
Foster saved Tottenham's first spot kick from Jamie O'Hara in the shootout. Foster then saw David Bentley crack his penalty wide as United netted all four of their kicks.
Foster added: "I did an awful lot of research on who takes penalties for Spurs. I'd been given a lot of information on which way they put kicks.
"The I-pod is Eric's innovation. It's an amazing tool, you can brush up straight away."
England boss Fabio Capello watched Foster's heroics in United's 4-1 shootout win.
And Ferguson said: "He'll be England's keeper for the next number of years. I just pray he has more luck with injuries."