Gathering information

Whatever the documentation says you need 
(everything from mutt to the kernel has a list)

The package(s) involved.

The version number. 

Does it happen on: 
Your box,
A test account, 
An account with default settings
Other distros, other versions of same distros
Other OSes?

People on IRC are amazingly responsive to "I think this crashes any browser/GNOME desktop/VM subsystem" and will disappear and then reappear and add "yup, crashes my box too!"