Keane netted his 42nd and 43rd international goals to put the gloss on a fine night's work for Giovanni Trapattoni's side, who had claimed a first-half lead through Paul Green's brave header.
Algeria take on England in their World Cup Group C showdown in Cape Town on June 18, but on this evidence will present little problems to Fabio Capello's team.
Toon legend David Ginola fancies England's chances in the competition.
David Ginola: "I think England have got a great chance of winning the World Cup. They have some great players but they need to work as a team."