should be no need to pay again... cause i also paid for quite a lot of cydia apps when i was using 3GS... when i got the iPhone4 for moi wifey, i use back the same google a/c, can re-dload those apps.
Cool bro, thks for the heads-up...i've recently cooled off on the purchase of cydia apps cos i'm worried on the "re-usability" of the purchased apps for future generations of iPhone. Think i bought one too many

Now with ur information, I may top up my paypal account & go on a shopping spree again

