The Lanky forward joined the Cobblers from Scarborough for £45K in 2002 and scored five times for them last season as the club were relegated from the Second Division.
Stamp joined United in July 1997 from Hessle and made his debut in the 2-0 win over Hull at Boothferry Park in September. While at Glanford Park he made 17 appearances, 12 of them from the subs bench, and scored just one goal.
He sparked a row between Iron manager Brian Laws and then Carlisle boss Ian Atkins in 2001.
Stamp had been offered a deal by Carlisle United to prevent him signing for the relegation rivals Exeter, but pulled out at the last minute after keeping him in their reception all afternoon on transfer deadline day - stopping him from agreeing a two year deal with Exeter and forcing him to drop to the Conference with Scarborough after being released by United in the summer.