There is a thread on macrumors that probably will answer to your question here are some quotes
Originally Posted by MrThompsonR:
“I would suggest using AptBackup ... It backs up your apps to your iTunes backup... After restoring from Backup.. Reinstall/ run this app to get all your Cydia(purchased/ free) apps reinstalled by tapping the "Restore" button. I run it whenever I add/ delete apps...then sync with iTunes.”
Originally Posted by f4780y:
“Cydia can't tell that you own the app until you identify yourself to it. You do that by trying to re-purchase something you already own. You won't be charged twice if you use the same details. Just log in and you should get the message that let's you add the new phone as a device on your account.
Then all your apps will show correctly as "purchased" in Cydia and you can install as normal.
pkgbackup is a great tool, but you would still have to do this step to download it on a new device. all it saves you is time and effort remembering all the packages you have to install.”
Originally Posted by maturola:
“Your apps are there just fine, all you need to do is to link your new iPhone Cydia with the ID that you used when you originally bought the app, Cydia use either facebook or google ID. For that. I don't remember exactly the step by step but just google it, once your new Cydia is link with that ID IT WILL show you what you already paid for.
Actually just hit "buy" for one of the app you bought it will ask you to login and the it will see that you already paid”
http://forums.macrumors.com/showthread.php?t=1036097
