I don't think it's possible. At least, not in the theory of teleportation. I'd believe returning to the past is impossible, because that's stating that what previously existed is already there. It would mean that the past is still taking place behind us in an infinite loop, because for us to travel backwards, there would have to be something in existence to travel to.
...I have no idea if that made sense.
Traveling forward to the future, however? Perhaps, but it would be a one-way trip. If you manage to travel faster than... well, time, I suppose, that didn't cause you to physically skip any period of time. Instead, you're simply moving across it at an accelerated rate. Everything is still taking place around you, you're just not able to interact with it at our currently established rate.
Like someone said about cryogenics. You can freeze yourself for a thousand years, still be the same age, weight, height, etc when you wake up, but you didn't actually skip what was going on physically. Everything still happened around you.
I guess it just depends on how you define "time travel".