Time is a very funny thing. It doesn't accually exist, yet it's there. Lets put it this way, the past doesn't exist, it's gone and you can't go back. The Future has not happened yet so it doesn't exist. (yes you can go to the future but it's relative) The present is constantly changing, similar to a rate. Time, if you will, is made up of infinate presents.

Time can also be thought of as spacetime, the fourth dimension. Space time, as we know from the discussion on black holes, can be warped by two things, mass and motion. There is an uncertainty principle much like that in physics/chamistry (says you can't know both the magnitude and location of an electron at the same time) for time and mass. It says that you cannot simultaneously know the mass and time of any object made up of matter. Mass in motion can warp spacetime. The faster you move, the more dense you get and the more time slows down around you. You are literally curving spacetime around you. As you aproach the speed of light (C) you become extremely dense and time substantually slows down around you. The equation for this is:

So, simply by moving you warp spacetime. Although you do have to move extremely fast to notice its effect. This has been proven in experimentation. A few years ago two atomic clocks were made with the exact same time. One was put in a room on Earth while the other was flown to space and orbited the Earth for some time. They were then brought back together and the clack that had orbited the Earth was a few milli-seconds or so behind. It was an extremely smal difference, but it proved the theory that time can be warped by motion as proposed by Einstein's relativity.

To go in another direction somewhat related to time, what if you could step out of time? This would be much like a three dimensional person stepping out of a two dimensional world. How would you describe a sphere to a two dimensional world? Anyway, if you stepped out of time you would experiance all time (all presents) all the time. You would not age or feel the effects of time passing. Truely, this is what God is, a being outside the barrier of time.