Midfielder thanks U's for opportunity.
And, as he prepared for life at Portman Road, he said: "I was there a long time and enjoyed my time at the club over the years and, after eight years, I felt that this is the right time for me to go.
His move to Town will present the next generation with the chance to fill his boots, with the likes of Alex Gilbey already having tasted first team action this season.
Having arrived as a fresh faced teenager into the U's youth team, Woody became a mainstay of the first team under a number of managers in the years that followed, playing 199 times for the club and scoring 35 goals.
"Colchester is a brilliant club, and I can't speak highly enough of everybody there. They gave me my opportunity in professional football and I will always be grateful for that in the years to come."