If you have upgraded to the latest Apple OS 3.0 or higher, all of your cracked apps might be lost as iTunes will not recognize them as purchased apps. You will need to repatch the OS with application called APPSYNC available in Cydia under the Hackulo.us repository.
-Go to Cydia
-Tap on Manage tab
-Tap on sources
-Tap on “Edit” and then on “Add” , type in the hackulo.us repository which is http://cydia.hackulo.us
-Tap on Add Source
-After the source is added, go to “Search” in Cydia and search for AppSync for OS 3.0
-Install and Confirm
-Select the applications you want and click sync, they will be synced without any errors
Now you can freely sync your jailbroken apps via iTunes to your iPod Touch 1G/2G and iPhone.
If you are using OS 4.0 on your iPhone/iPod Touch there is good news for you. Now, you can sync your cracked apps on your iPhone/iPod Touch with AppSync 4.0.
AppSync 4.0 patches MobileInstallation file on OS 4.0, and hence allows you to install .ipa files on iPhone/iPod Touch.
Note: Install a free app from iTunes before going for cracked apps.
AppSync 4.0 is available on Cydia via Hackulous repo for free.