After performing the 3.0 upgrade yesterday, all was well (I had updated and used several applications) but a few hours later all 3rd party apps refused to open. After selecting an app, it would start up for about 1-2 seconds then crash and revert back to the OS. I redownloaded/restored the phone, thinking my original download/install had been corrupted and everything started working again. Today, the same problem is happening again. Apps immediately crash upon being selected. ALL preinstalled Apple applications (iTunes, App Store, iPod, etc) continue to work fine. All my apps are completely up to date.