One problem i faced after upgrading my iPhone to 1.1.3 was the inability for the Installer to uninstall Summerboard and Taskbar Notifier. Since these apps do not have any “re-install” button in the Installer, i figured out a way to remove these phantom apps from the Installer database (an XML file). The easiest way to fix this is if you have a Mac because Mac OS X comes with a Property List Editor (you will have this if you have installed the Developer Tools).

• Connect to your iPhone using your favorite file transfer program (i was using Fugu).
• Go to this folder on the iPhone:
  /var/root/Library/Installer
• Download the LocalPackages.plist file to your Mac.
• Duplicate the LocalPackages.plist file so that you have a backup just in case you mess it up later.
• Double-click LocalPackages.plist. This will bring up the Property List Editor. You will see a list of numbers, like the screenshot below:
  
• Because i had two applications (Taskbar Notifier and Summerboard) that i could not uninstall, the first two numbers (0 and 1) were for them respectively. The screenshots with the expanded list are shown below:
  
  
• Select 0 and click on the “Delete” button. This will get rid of the first uninstallable app. When first “0″ has been deleted, Property List Editor will shift every item up one, so what used to be “1″ (Summerboard) will now be “0″. Delete it again. Note that your uninstallable apps may be on different property list numbers.
• When you are done deleting the phantom apps, save the plist file.
• Transfer back to the exact same location where the LocalPackages.plist file was first retrieved to replace the existing file there.
• When you start Installer.app again, the phantom apps will be gone.