How do I start debuging crashes?

[Joseph Wang]

Hi,

I'd like to help starting to improve the stablity of mozilla and was
wondering how I would go about reporting segmentation fault crashes. 
I'm
not sure that reporting that mozilla crashes on page X some of the time
would be that useful, and was wondering how I would go about making
useful
crash reports (i.e. is there some sort of file with information about
where mozilla crashed that I could mail out with my bug report).

Thanks!!!!