Miller, who made his name at Hartlepool before moving to Ipswich, has scored over 100 goals in his career.
He has also played for Sunderland, Ipswich, Huddersfield and Sheffield Wednesday.
Manager Kevin Blackwell told the club's official website: "Tommy brings a wealth of experience that is needed at this level.
"He is excellent on the ball and is one of the key players I have been trying to bring to the club.
''He had offers at higher levels but he was very impressed with the new set-up here at Gigg Lane. He will be a great asset."