Randomly shuts down :(

I have a Dual Core 1.83, 15" Macbook Pro and just recently it has just started to shut down randomly, sometimes frequently, sometimes not for days. Any ideas? I am going crazy.

Have the same problem. It is going to make me a lot of trouble as it is shuts down randomly. But I guess it is the battery as many ppl on the net suggest.
Try to look at your battery when it shut down. If it shows low capacity when is actually full then you probably have a faulty battery - take it Apple...
I'm going there asap.
good luck

If you want to test and see if its your battery, you can try to take it out and use AC power only. If it continues to randomy shutdown, you can eliminate the battery as the source of problems.