The 25-year-old confirmed he watched a spot-kick taken by Jamie O'Hara in the UEFA Cup defeat to PSV Eindhoven last season - and then saved his penalty at Wembley.
In that game, O'Hara fired a shot to the left of the goalkeeper and on Sunday he sent Tottenham's first penalty the same way and Foster saved.
The idea of using an iPod as a tactical aid is new and not against the laws of the game. It brings into question a loophole in FIFA's regulations with regards to the use of technology and it is possible they could now move to tighten up their rules.
An FA spokesman said: "What happened was not against the rules so we will not be investigating the matter further."
Foster said: "Just before the shootout I was looking at an iPod with goalkeeping coach Eric Steele and it contained images of Tottenham's players taking penalties.
"They told me for Jamie O'Hara I should stand up and be strong and he would probably go the way he did. I have done a lot of research before but this is an innovation we have brought in at the club."