It would will still take a lot of work to make colonization practical. We're likely to start off sending probes to get a look at the planet itself, then likely use something more in the line of a robot to start terraforming remotely, and only start sending colony ships once the brute work is done. We're talking centuries of work.
Hell of a payoff, though.
Barring some major catastrophe that kills a large chunk of the human population, yet leaves the Earth still largely habitable, we're gonna have to go to other planets, eventually. Even if we completely cut our dependence on all non-renewable fuels and can make food out of energy, we're gonna reach a point, population-wise, where one of two things will have to happen: we spread to other planets, or we enforce population control like what's seen in Ender's Game, perhaps even worse.
Personally, for the simple sake of freedom, I much prefer the former over the latter. Plus, space travel kicks ass.