iPhone Crash Logs
If your have an application that is crashing then the developers may/should ask you to send him the crash log so they can attempt to diagnose the problem. This logfile contains information about what the application was doing before it crashed.
These log files are stored on your computer, and are copied across everytime you sync your iPhone. To find the log files do the following;
1) Sync your iPhone
2) Browse to the following folders. Note that DEVICE_NAME will be the name if your iPhone as shown in iTunes.
Mac OS X : /Library/Logs/CrashReporter/MobileDevice// Windows XP: C:\Documents and Settings\\Application Data\Apple computer\Logs\CrashReporter\\ Windows Vista: C:\Users\\AppData\Roaming\Apple computer\Logs\CrashReporter\MobileDevice\\
3) Each log file will begin with the name of the application. Create a zip file from these applications (Mac: Right-click->Compress, Windows Right-Click->WinZip) and then email it to the developer