Application crash logs are transfered to your computer each time you do a sync with the device, in the iTunes. Thus, first step is to sync with iTunes:
Mac OS X –
On the Mac, crash logs are kept at:
where ~ is your Home folder.
Windows Vista –
Files are located here:
AppData folder is hidden by default, , so you need to reveal it by typing the address in My Computer’s address bar.
Windows XP –
Location is here:
C:/Documents and Settings/<USERNAME>/Application Data/Apple computer/LogsCrashReporter/<DEVICE_NAME>
<USERNAME> is your login username.
Application Data folder is usually hidden by default, so you need to reveal it in the same way as in Vista — by typing in and pressing Enter.