How to find crash logs for iPhone applications on Mac, Vista and XP
iTunesConnect service — a web site that iPhone developers use to manage
their published applications — has a separate area that will list all the
synced crash reports from the application users.
However, not all of the crashes appear there, or are slow to appear.
Thus, if you have a desperate problem with someone’s application, it’s a good
idea to pick these up and send them to a developer.
Here’s how, in three major operations systems: Mac OS X,
Windows Vista / Windows 7 and for
Windows XP.
iTunes sync
Application crash logs are transferred to your computer each time you do a
sync with the device, in the iTunes. Thus, first step is to sync with iTunes:

Sync your iOS device with iTunes.
Mac OS X
On the Mac, crash
logs are kept at:
~/Library/Logs/CrashReporter/MobileDevice/<DEVICE_NAME> (where ~ is your Home folder)
Here’s an example, showing the crash logs on the Mac OS X. Device name is “iPhone AV” here:

There’s
the .crash file and .plist file – archive them both and
send to a developer. Actually, pick all the files you find there that have the
name of the problematic application.
Windows Vista / Windows 7
Files are located
here:
C:\Users\<USERNAME>\AppData\Roaming\Apple computer\Logs\CrashReporter\MobileDevice\<DEVICE_NAME>
AppData folder
is hidden by default, so here’s how to access it. Open a "Computer" window to your personal folder: C:\Users\<USERNAME>

Then click on the address bar at the top which will
change the display into Windows folder path, add \AppData to it, then
click Enter:
C:\Users\<USERNAME>\AppData
Now the App Data folder contents are visible, and you can open the rest of the path to the Crash Logs:
C:\Users\<USERNAME>\AppData\Roaming\Apple computer\Logs\CrashReporter\MobileDevice\<DEVICE_NAME>
Windows XP
Location
is here:
C:\Documents and Settings\<USERNAME>\Application Data\Apple computer\Logs\CrashReporter\<DEVICE_NAME>
ref: http://aplus.rs/apple/how-to-find-crash-logs-for-iphone-applications-on-mac-vista-and-xp/