Ok, I'm coming in a little late because I just got to this thread, but here's my thoughts.

I think time is a concept, just as distance is. The measurement of both are human creations. We don't know what is at both ends of time and we don't know what's way out there. They are both infinite continuums and our measurements give them some sense of sanity. Time is measured by events. Sometime happens and it takes a certain amount of "time" so we can compare that measurement to other events. As long as something is happening, there is time. That's why when something takes a long time, it seems relative because you don't have smaller intervals with which to measure it. It's the same for travelling long distances. You can't really tell the difference between 1000 km and 10000 km without something else to measure it. Using a meter to measure something is just like using a minute. You can say that there is a meter between this and this in the same way that you can say that there is a minute between that and that. They are both events in their respective dimensions. A meter is an event that measures distance, a minute is an event that measures time.

As for there being no time before the Big Bang, I guess I can agree with that, until we determine what was there before. With the universe being as big as it is, it's fully possible that there are other galaxy clusters just like our "universe" farther away than we can perceive. And who says there wasn't anything in this locality long before the Big Bang. The matter for the Bang had to get here somehow. Saying that it just appeared is just as futile as saying that some god just materialized from nothing and created everything. Both are against the laws of physics.

I don't really think there will be an end to time either. Right now the current speculation to the end of the universe is not a big crunch, but just a continued expansion until everything is so far apart it's like it's not there at all. Time had a feature about this a few months ago. As T.S. Eliot said: "This is the way the world ends, and not with a bang, but a wimper." This doesn't necessarily mark the end of time though, because a planet floating away is still something happening.

I'm not really sure how much of this makes sense, because I'm not totally sure what I'm trying to say, but there it is anyway.