Since the recent update to 2.0.2, many users reported that their applications crash really often when trying to open them. A few fix were offered, including decreasing the amount of iPhone applications on your device or, downgrading to an earlier version of iTunes.
These 2 fixes delivered different results but it seems the folks at iPhone Atlas finally discovered a real fix to this problem.
On the iPhone, select Settings > General > Erase all Content and Settings.
On a Mac, delete the following support files from the computer:
/Library/Receipts/AppleMobileDeviceSupport.pkg
/Library/Receipts/iTunesAccess.pkg
/Library/Receipts/iTunesX.pkg
~/Library/iTunes/Device Support (the entire folder)
/System/Library/Extensions/AppleMobileDevice.kext
/System/Library/PrivateFrameworks/DeviceLink.framework
/System/Library/PrivateFrameworks/MobileDevice.framework
~/Library/iTunes/iPhone Software Updates (all contents)
On a Windows XP PC, delete the files in settings/[yourusername]/Application Data/Apple Computer/iTunes/iPhone Software Updates
On a Windows Vista PC, delete the files in C:/users/[yourusername]/AppData/Roaming/Apple Computer/iTunes/iPhone Software Updates
Delete the iTunes application
Restart the computer
Install iTunes 7.7
This method is obviously not for the average noobie as it requires some basics skills but that's the only solution so far to fix this issue with your iPhone.... at leat until Apple releases a new firmware update.
Thanks iPhone Atlas