System preferences crashes when press accounts
You might get better answers if you provide more information such as when this started happening.  For example, did you add a new account recently?  Install any applications recently?

Normally, when weird stuff happens on OS X such as crashes, repairing permissions can be a good place to start.  Try opening Disk Utility and select your computers Hard Drive on the left hand side, then click 'Repair Permissions'.  This will take a few minutes and may solve your problem.  Try a restart after the repair before you go back into Accounts.  

Have you tried this under a different user account?  I've come across instances of people having this only occur on one account.  You could create a new account and restore documents etc from a backup.