I was driving last night at about 50-60 mph and the engine just stalled and I haven't been able to get the car started again since. Well, I have actually got it restarted a couple times for a few seconds, but then it just stalled again. There are no signs that it is an electrical problem (I listened to the radio for 30 minutes waiting for the tow truck and nothing flickered; when I did try to restart it, the battery light didn't stay on unusually long and it went off whenever the engine appeared to be starting).

My best guess at this point is either the fuel pump, the timing belt, or a filter. After reading the timing belt thread above, I suspect that is probably the issue (or perhaps the tensioner or the idler?). The car has approx 91K miles on it and none of those items have been replaced yet - it's my wife's car and I know she's taken it in for all the regularly scheduled maintenance with the dealer, but she confirmed that none of those items have been replaced. What should I look for to confirm that it's the timing belt? Keep in mind that I am a mechanical novice - I don't even know where the timing belt is. Assuming that is the problem, what I am looking at to get it replaced? $700-$800?

Any other ideas about what the problem could be? Thanks in advance for all your help.