The forward is leaving Portman Road after being transfer listed by the club due to his high wages, and the fee of £450,000 includes £300,000 up front and £150,000 to follow in June 2005.
Speaking of the departure of the £3M signing from Blackburn by ex boss George Burley, Town boss Joe Royle told itfc.co.uk: "Marcus only had 12 months left on his contract and is also one of our higher wage earners so the move makes sense for us.
"It's also a good opportunity for Marcus. Everton are a great club with a marvellous tradition and I wish him the best of luck there."