Is offered here.
It's interesting. But that's not necessarily the first solution. I mean its nice to dream about in the very long term, but right now we're talking about a trip of several thousand years to get to the closest star (to say nothing of a star we'd want to get to for some other reason).
You could imagine some sort of cryogenic human payload that we could send out much slower, much smaller, and much sooner. Granted, it would take some advances in cryogenics. But I imagine that would come sooner than bending space-time (which is really what inter-stellar travel would take). Develop cryogenics, freeze some intrepid colonists, set the timer, wake them up a year or two out from their destination so they can build up strength, etc. Or better yet, unfreeze the pilot and a couple others a year or two in advance and have them - with mechanized help - set up greenhouses and shelters before waking everyone else up on the destination planet. You would need a big ship, but you wouldn't need a massive one of the sort that people usually think about for inter-stellar travel.
By the time we get cryogenics in good shape we'll probably have a much better sense of what exoplanets are "livable". Then send off a bunch of these ships and seed the galaxy with human (and presumably other terrestrial) life. If we learn how to bend space time, fine - we'll beat the popsicles to these planets. If we don't learn how to bend space-time then its good to have sent them out. And if we all kill each other here on Earth it's very good that we sent them out.
The real concern is whether they can make it: whether the cryogenics is good enough. When we're talking about settling worlds outside our solar system, it's a one way ticket. So who really cares if it happens thousands and thousands of years after you and I are dead? Who cares if these popsicles are floating through space for millenia. When they touch down what's going on on Earth is completely irrelevant.
This would be extremely expensive, of course. And you need to wait for some science to be developed. But once it is we really need to consider insurance policies like this.