I jailbroke my 3.1.2 3GS last week using PwnageTool. No problems whatsoever. However, in the week since then, I've noticed iTunes on my Mac says I have several updates for various (legit paid for) App Store apps I have installed, but when I run the App Store on my iPhone, it doesn't show the new apps. I tried updating the apps on my computer then syncing to get the updated versions, but the new apps wouldn't sync. It's like the phone thinks whatever I have installed is always the latest version even when that isn't true. Anyone else ever had this problem?