Whats that movie called...
 

...where there is this guy that steals money from his company that he works at and keeps changing the amount of money he has stolen when he is asked. When he goes to jail he tells that he even stole more money then he had said before. He thought he was doing no harm the whole time.

Sounds like one of these

http://www.imdb.com/title/tt0285861/
http://www.imdb.com/title/tt1130080/

you mean "i love you philip morris" ?

Sounds something like The Informant but I dont think Damon goes to jail.

The Informant! - Rotten Tomatoes

thanks guys. it was the Informant that i was looking for